



SACM Working Group                                           H. Birkholz
Internet-Draft                                            Fraunhofer SIT
Intended status: Standards Track                     J. Fitzgerald-McKay
Expires: 20 January 2023                        National Security Agency
                                                              C. Schmidt
                                                   The MITRE Corporation
                                                           D. Waltermire
                                                                    NIST
                                                            19 July 2022


                  Concise Software Identification Tags
                       draft-ietf-sacm-coswid-22

Abstract

   ISO/IEC 19770-2:2015 Software Identification (SWID) tags provide an
   extensible XML-based structure to identify and describe individual
   software components, patches, and installation bundles.  SWID tag
   representations can be too large for devices with network and storage
   constraints.  This document defines a concise representation of SWID
   tags: Concise SWID (CoSWID) tags.  CoSWID supports a similar set of
   semantics and features as SWID tags, as well as new semantics that
   allow CoSWIDs to describe additional types of information, all in a
   more memory efficient format.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 20 January 2023.

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  The SWID and CoSWID Tag Lifecycle . . . . . . . . . . . .   4
     1.2.  Concise SWID Format . . . . . . . . . . . . . . . . . . .   8
     1.3.  Requirements Notation . . . . . . . . . . . . . . . . . .   8
   2.  Concise SWID Data Definition  . . . . . . . . . . . . . . . .   8
     2.1.  Character Encoding  . . . . . . . . . . . . . . . . . . .  10
     2.2.  Concise SWID Extensions . . . . . . . . . . . . . . . . .  10
     2.3.  The concise-swid-tag Map  . . . . . . . . . . . . . . . .  13
     2.4.  concise-swid-tag Co-Constraints . . . . . . . . . . . . .  17
     2.5.  The global-attributes Group . . . . . . . . . . . . . . .  18
     2.6.  The entity-entry Map  . . . . . . . . . . . . . . . . . .  19
     2.7.  The link-entry Map  . . . . . . . . . . . . . . . . . . .  20
     2.8.  The software-meta-entry Map . . . . . . . . . . . . . . .  25
     2.9.  The Resource Collection Definition  . . . . . . . . . . .  28
       2.9.1.  The hash-entry Array  . . . . . . . . . . . . . . . .  28
       2.9.2.  The resource-collection Group . . . . . . . . . . . .  28
       2.9.3.  The payload-entry Map . . . . . . . . . . . . . . . .  32
       2.9.4.  The evidence-entry Map  . . . . . . . . . . . . . . .  32
     2.10. Full CDDL Specification . . . . . . . . . . . . . . . . .  33
   3.  Determining the Type of CoSWID  . . . . . . . . . . . . . . .  39
   4.  CoSWID Indexed Label Values . . . . . . . . . . . . . . . . .  40
     4.1.  Version Scheme  . . . . . . . . . . . . . . . . . . . . .  40
     4.2.  Entity Role Values  . . . . . . . . . . . . . . . . . . .  42
     4.3.  Link Ownership Values . . . . . . . . . . . . . . . . . .  44
     4.4.  Link Rel Values . . . . . . . . . . . . . . . . . . . . .  44
     4.5.  Link Use Values . . . . . . . . . . . . . . . . . . . . .  46
   5.  URI Schemes . . . . . . . . . . . . . . . . . . . . . . . . .  47
     5.1.  "swid" URI Scheme . . . . . . . . . . . . . . . . . . . .  47
     5.2.  "swidpath" URI Scheme . . . . . . . . . . . . . . . . . .  48
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  49
     6.1.  CoSWID Items Registry . . . . . . . . . . . . . . . . . .  49
     6.2.  Software ID Values Registries . . . . . . . . . . . . . .  52
       6.2.1.  Registration Procedures . . . . . . . . . . . . . . .  52
       6.2.2.  Private Use of Index and Name Values  . . . . . . . .  52
       6.2.3.  Expert Review Criteria  . . . . . . . . . . . . . . .  53
       6.2.4.  Software ID Version Scheme Values Registry  . . . . .  53
       6.2.5.  Software ID Entity Role Values Registry . . . . . . .  55



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       6.2.6.  Software ID Link Ownership Values Registry  . . . . .  56
       6.2.7.  Software ID Link Relationship Values Registry . . . .  57
       6.2.8.  Software ID Link Use Values Registry  . . . . . . . .  60
     6.3.  swid+cbor Media Type Registration . . . . . . . . . . . .  61
     6.4.  CoAP Content-Format Registration  . . . . . . . . . . . .  62
     6.5.  CBOR Tag Registration . . . . . . . . . . . . . . . . . .  62
     6.6.  URI Scheme Registrations  . . . . . . . . . . . . . . . .  62
       6.6.1.  URI-scheme swid . . . . . . . . . . . . . . . . . . .  63
       6.6.2.  URI-scheme swidpath . . . . . . . . . . . . . . . . .  63
     6.7.  CoSWID Model for use in SWIMA Registration  . . . . . . .  64
   7.  Signed CoSWID Tags  . . . . . . . . . . . . . . . . . . . . .  64
   8.  CBOR-Tagged CoSWID Tags . . . . . . . . . . . . . . . . . . .  67
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  67
   10. Privacy Consideration . . . . . . . . . . . . . . . . . . . .  71
   11. Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .  72
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  77
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  77
     12.2.  Informative References . . . . . . . . . . . . . . . . .  80
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  81
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  81
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  82

1.  Introduction

   SWID tags, as defined in ISO-19770-2:2015 [SWID], provide a
   standardized XML-based record format that identifies and describes a
   specific release of software, a patch, or an installation bundle,
   which are referred to as software components in this document.
   Different software components, and even different releases of a
   particular software component, each have a different SWID tag record
   associated with them.  SWID tags are meant to be flexible and able to
   express a broad set of metadata about a software component.

   SWID tags are used to support a number of processes including but not
   limited to:

   *  Software Inventory Management, a part of a Software Asset
      Management [SAM] process, which requires an accurate list of
      discernible deployed software components.

   *  Vulnerability Assessment, which requires a semantic link between
      standardized vulnerability descriptions and software components
      installed on IT-assets [X.1520].

   *  Remote Attestation, which requires a link between reference
      integrity measurements (RIM) and Attester-produced event logs that
      complement attestation evidence [I-D.ietf-rats-architecture].




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   While there are very few required fields in SWID tags, there are many
   optional fields that support different uses.  A SWID tag consisting
   of only required fields might be a few hundred bytes in size;
   however, a tag containing many of the optional fields can be many
   orders of magnitude larger.  Thus, real-world instances of SWID tags
   can be fairly large, and the communication of SWID tags in usage
   scenarios, such as those described earlier, can cause a large amount
   of data to be transported.  This can be larger than acceptable for
   constrained devices and networks.  Concise SWID (CoSWID) tags
   significantly reduce the amount of data transported as compared to a
   typical SWID tag through the use of the Concise Binary Object
   Representation (CBOR) [RFC8949].

   Size comparisons between XML SWID and CoSWID mainly depend on domain-
   specific applications and the complexity of attributes used in
   instances.  While the values stored in CoSWID are often unchanged and
   therefore not reduced in size compared to an XML SWID, the
   scaffolding that the CoSWID encoding represents is significantly
   smaller by taking up 10 percent or less in size.  This effect is
   visible in representation sizes, which in early experiments benefited
   from a 50 percent to 85 percent reduction in generic usage scenarios.
   Additional size reduction is enabled with respect to the memory
   footprint of XML parsing/validation.

   In a CoSWID, the human-readable labels of SWID data items are
   replaced with more concise integer labels (indices).  This approach
   allows SWID and CoSWID to share a common implicit information model,
   with CoSWID providing an alternate data model [RFC3444].  While SWID
   and CoSWID are intended to share the same implicit information model,
   this specification does not define this information model, or a
   mapping between the two data formats.  While an attempt to align SWID
   and CoSWID tags has been made here, future revisions of ISO/IEC
   19770-2:2015 or this specification might cause this implicit
   information model to diverge, since these specifications are
   maintained by different standards groups.

   The use of CBOR to express SWID information in CoSWID tags allows
   both CoSWID and SWID tags to be part of an enterprise security
   solution for a wider range of endpoints and environments.

1.1.  The SWID and CoSWID Tag Lifecycle

   In addition to defining the format of a SWID tag record, ISO/IEC
   19770-2:2015 defines requirements concerning the SWID tag lifecycle.
   Specifically, when a software component is installed on an endpoint,
   that software component's SWID tag is also installed.  Likewise, when
   the software component is uninstalled or replaced, the SWID tag is
   deleted or replaced, as appropriate.  As a result, ISO/IEC



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   19770-2:2015 describes a system wherein there is a correspondence
   between the set of installed software components on an endpoint, and
   the presence of the corresponding SWID tags for these components on
   that endpoint.  CoSWIDs share the same lifecycle requirements as a
   SWID tag.

   The SWID specification and supporting guidance provided in NIST
   Internal Report (NISTIR) 8060: Guidelines for the Creation of
   Interoperable SWID Tags [SWID-GUIDANCE] defines four types of SWID
   tags: primary, patch, corpus, and supplemental.  The following text
   is paraphrased from these sources.

   1.  Primary Tag - A SWID or CoSWID tag that identifies and describes
       an installed software component on an endpoint.  A primary tag is
       intended to be installed on an endpoint along with the
       corresponding software component.

   2.  Patch Tag - A SWID or CoSWID tag that identifies and describes an
       installed patch that has made incremental changes to a software
       component installed on an endpoint.  A patch tag is intended to
       be installed on an endpoint along with the corresponding software
       component patch.

   3.  Corpus Tag - A SWID or CoSWID tag that identifies and describes
       an installable software component in its pre-installation state.
       A corpus tag can be used to represent metadata about an
       installation package or installer for a software component, a
       software update, or a patch.

   4.  Supplemental Tag - A SWID or CoSWID tag that allows additional
       information to be associated with a referenced SWID tag.  This
       allows tools and users to record their own metadata about a
       software component without modifying CoSWID primary or patch tags
       created by a software provider.

   The type of a tag is determined by specific data elements, which are
   discussed in Section 3, which also provides normative language for
   CoSWID semantics that implement this lifecycle.  The following
   information helps to explain how these semantics apply to use of a
   CoSWID tag.

      Corpus, primary, and patch tags have similar functions in that
      they describe the existence and/or presence of different types of
      software components (e.g., software installers, software
      installations, software patches), and, potentially, different
      states of these software components.  Supplemental tags have the
      same structure as other tags, but are used to provide information
      not contained in the referenced corpus, primary, and patch tags.



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      All four tag types come into play at various points in the
      software lifecycle and support software management processes that
      depend on the ability to accurately determine where each software
      component is in its lifecycle.

                                    +------------+
                                    v            |
  Software      Software        Software     Software      Software
  Deployment -> Installation -> Patching  -> Upgrading  -> Removal

  Corpus        Primary         Primary      xPrimary      xPrimary
  Supplemental  Supplemental    Supplemental xSupplemental xSupplemental
                                Patch        xPatch
                                             Primary
                                             Supplemental

           Figure 1: Use of Tag Types in the Software Lifecycle

      Figure 1 illustrates the steps in the software lifecycle and the
      relationships among those lifecycle events supported by the four
      types of SWID and CoSWID tags.  A detailed description of the four
      tags types is provided in Section 2.3.  The figure identifies the
      types of tags that are used in each lifecycle event.

   There are many ways in which software tags might be managed for the
   host the software is installed on.  For example, software tags could
   be made available on the host or to an external software manager when
   storage is limited on the host.

   In these cases the host or external software manager is responsible
   for management of the tags, including deployment and removal of the
   tags as indicated by the above lifecycle.  Tags are deployed and
   previously deployed tags that are typically removed (indicated by an
   "x" prefix) at each lifecycle stage, as follows:

      -  Software Deployment.  Before the software component is
         installed (i.e., pre-installation), and while the product is
         being deployed, a corpus tag provides information about the
         installation files and distribution media (e.g., CD/DVD,
         distribution package).

   Corpus tags are not actually deployed on the target system but are
   intended to support deployment procedures and their dependencies at
   install-time, such as to verify the installation media.

      -  Software Installation.  A primary tag will be installed with
         the software component (or subsequently created) to uniquely
         identify and describe the software component.  Supplemental



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         tags are created to augment primary tags with additional site-
         specific or extended information.  While not illustrated in the
         figure, patch tags can also be installed during software
         installation to provide information about software fixes
         deployed along with the base software installation.

      -  Software Patching.  A new patch tag is provided, when a patch
         is applied to the software component, supplying details about
         the patch and its dependencies.  While not illustrated in the
         figure, a corpus tag can also provide information about the
         patch installer and patching dependencies that need to be
         installed before the patch.

      -  Software Upgrading.  As a software component is upgraded to a
         new version, new primary and supplemental tags replace existing
         tags, enabling timely and accurate tracking of updates to
         software inventory.  While not illustrated in the figure, a
         corpus tag can also provide information about the upgrade
         installer and dependencies that need to be installed before the
         upgrade.

   Note: In the context of software tagging software patching and
   updating differ in an important way.  When installing a patch, a set
   of file modifications are made to pre-installed software which do not
   alter the version number or the descriptive metadata of an installed
   software component.  An update can also make a set of file
   modifications, but the version number or the descriptive metadata of
   an installed software component are changed.

      -  Software Removal.  Upon removal of the software component,
         relevant SWID tags are removed.  This removal event can trigger
         timely updates to software inventory reflecting the removal of
         the product and any associated patch or supplemental tags.

   As illustrated in the figure, supplemental tags can be associated
   with any corpus, primary, or patch tag to provide additional metadata
   about an installer, installed software, or installed patch
   respectively.

   Understanding the use of CoSWIDs in the software lifecycle provides a
   basis for understanding the information provided in a CoSWID and the
   associated semantics of this information.  Each of the different SWID
   and CoSWID tag types provide different sets of information.  For
   example, a "corpus tag" is used to describe a software component's
   installation image on an installation media, while a "patch tag" is
   meant to describe a patch that modifies some other software
   component.




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1.2.  Concise SWID Format

   This document defines the CoSWID tag format, which is based on CBOR.
   CBOR-based CoSWID tags offer a more concise representation of SWID
   information as compared to the XML-based SWID tag representation in
   ISO-19770-2:2015.  The structure of a CoSWID is described via the
   Concise Data Definition Language (CDDL) [RFC8610].  The resulting
   CoSWID data definition is aligned to the information able to be
   expressed with the XML schema definition of ISO-19770-2:2015 [SWID].
   This alignment allows both SWID and CoSWID tags to represent a common
   set of software component information and allows CoSWID tags to
   support the same uses as a SWID tag.

   The vocabulary, i.e., the CDDL names of the types and members used in
   the CoSWID CDDL specification, are mapped to more concise labels
   represented as small integer values (indices).  The names used in the
   CDDL specification and the mapping to the CBOR representation using
   integer indices is based on the vocabulary of the XML attribute and
   element names defined in ISO/IEC 19770-2:2015.

1.3.  Requirements Notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Concise SWID Data Definition

   The following describes the general rules and processes for encoding
   data using CDDL representation.  Prior familiarity with CBOR and CDDL
   concepts will be helpful in understanding this CoSWID specification.

   This section describes the conventions by which a CoSWID is
   represented in the CDDL structure.  The CamelCase [CamelCase]
   notation used in the XML schema definition is changed to a hyphen-
   separated notation [KebabCase] (e.g., ResourceCollection is named
   resource-collection) in the CoSWID CDDL specification.  This
   deviation from the original notation used in the XML representation
   reduces ambiguity when referencing certain attributes in
   corresponding textual descriptions.  An attribute referred to by its
   name in CamelCase notation explicitly relates to XML SWID tags; an
   attribute referred to by its name in KebabCase notation explicitly
   relates to CBOR CoSWID tags.  This approach simplifies the
   composition of further work that reference both XML SWID and CBOR
   CoSWID documents.




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   In most cases, mapping attribute names between SWID and CoSWID can be
   done automatically by converting between CamelCase and KebabCase
   attribute names.  However, some CoSWID CDDL attribute names show
   greater variation relative to their corresponding SWID XML Schema
   attributes.  This is done when the change improves clarity in the
   CoSWID specification.  For example, the "name" and "version" SWID
   fields corresponds to the "software-name" and "software-version"
   CoSWID fields, respectively.  As such, it is not always possible to
   mechanically translate between corresponding attribute names in the
   two formats.  In such cases, a manual mapping will need to be used.
   XPath expressions [W3C.REC-xpath20-20101214] need to use SWID names,
   see Section 5.2.

   The 57 human-readable text labels of the CDDL-based CoSWID vocabulary
   are mapped to integer indices via a block of rules at the bottom of
   the definition.  This allows a more concise integer-based form to be
   stored or transported, as compared to the less efficient text-based
   form of the original vocabulary.

   Through use of CDDL-based integer labels, CoSWID allows for future
   expansion in subsequent revisions of this specification and through
   extensions (see Section 2.2).  New constructs can be associated with
   a new integer index.  A deprecated construct can be replaced by a new
   construct with a new integer index.  An implementation can use these
   integer indexes to identify the construct to parse.  The CoSWID Items
   registry, defined in Section 6.1, is used to ensure that new
   constructs are assigned a unique index value.  This approach avoids
   the need to have an explicit CoSWID version.

   In a number of places, the value encoding admits both integer values
   and text strings.  The integer values are defined in a registry
   specific to the kind of value; the text values are not intended for
   interchange and exclusively meant for private use as defined in
   Section 6.2.2.  Encoders SHOULD NOT use string values based on the
   names registered in the registry, as these values are less concise
   than their index value equivalent; a decoder MUST however be prepared
   to accept text strings that are not specified in this document (and
   ignore the construct if that string is unknown).  In the rest of the
   document, we call this an "integer label with text escape".

   The root of the CDDL specification provided by this document is the
   rule coswid (as defined in Section 8):

   start = coswid

   In CBOR, an array is encoded using bytes that identify the array, and
   the array's length or stop point (see [RFC8949]).  To make items that
   support 1 or more values, the following CDDL notation is used.



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   _name_ = (_label_ => _data_ / [ 2* _data_ ])

   The CDDL rule above allows either a single data item or an array of 2
   or more data values to be provided.  When a singleton data value is
   provided, the CBOR markers for the array, array length, and stop
   point are not needed, saving bytes.  When two or more data values are
   provided, these values are encoded as an array.  This modeling
   pattern is used frequently in the CoSWID CDDL specification to allow
   for more efficient encoding of singleton values.

   Usage of this construct can be simplified using

   one-or-more<T> = T / [ 2* T ]

   simplifying the above example to

   _name_ = (_label_ => one-or-more<_data_>)

   The following subsections describe the different parts of the CoSWID
   model.

2.1.  Character Encoding

   The CDDL "text" type is represented in CBOR as a major type 3, which
   represents "a string of Unicode characters that [are] encoded as
   UTF-8 [RFC3629]" (see Section 3.1 of [RFC8949]).  Thus both SWID and
   CoSWID use UTF-8 for the encoding of characters in text strings.

   To ensure that UTF-8 character strings are able to be encoded/decoded
   and exchanged interoperably, text strings in CoSWID MUST be encoded
   consistent with the Net-Unicode definition defined in [RFC5198].

   All names registered with IANA according to requirements in
   Section 6.2 also MUST be valid according to the XML Schema NMTOKEN
   data type (see [W3C.REC-xmlschema-2-20041028], Section 3.3.4) to
   ensure compatibility with the SWID specification where these names
   are used.

2.2.  Concise SWID Extensions

   The CoSWID specification contains two features that are not included
   in the SWID specification on which it is based.  These features are:

   *  The explicit definition of types for some attributes in the ISO-
      19770-2:2015 XML representation that are typically represented by
      the "any attribute" in the SWID model.  These are covered in
      Section 2.5.




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   *  The inclusion of extension points in the CoSWID specification
      using CDDL sockets (see Section 3.9 of [RFC8610]).  The use of
      CDDL sockets allow for well-formed extensions to be defined in
      supplementary CDDL descriptions that support additional uses of
      CoSWID tags that go beyond the original scope of ISO-19770-2:2015
      tags.

   The following CDDL sockets (extension points) are defined in this
   document, which allow the addition of new information structures to
   their respective CDDL groups.









































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    +=====================+=================================+=========+
    | Map Name            | CDDL Socket                     | Defined |
    |                     |                                 | in      |
    +=====================+=================================+=========+
    | concise-swid-tag    | $$coswid-extension              | Section |
    |                     |                                 | 2.3     |
    +---------------------+---------------------------------+---------+
    | entity-entry        | $$entity-extension              | Section |
    |                     |                                 | 2.6     |
    +---------------------+---------------------------------+---------+
    | link-entry          | $$link-extension                | Section |
    |                     |                                 | 2.7     |
    +---------------------+---------------------------------+---------+
    | software-meta-entry | $$software-meta-extension       | Section |
    |                     |                                 | 2.8     |
    +---------------------+---------------------------------+---------+
    | resource-collection | $$resource-collection-extension | Section |
    |                     |                                 | 2.9.2   |
    +---------------------+---------------------------------+---------+
    | file-entry          | $$file-extension                | Section |
    |                     |                                 | 2.9.2   |
    +---------------------+---------------------------------+---------+
    | directory-entry     | $$directory-extension           | Section |
    |                     |                                 | 2.9.2   |
    +---------------------+---------------------------------+---------+
    | process-entry       | $$process-extension             | Section |
    |                     |                                 | 2.9.2   |
    +---------------------+---------------------------------+---------+
    | resource-entry      | $$resource-extension            | Section |
    |                     |                                 | 2.9.2   |
    +---------------------+---------------------------------+---------+
    | payload-entry       | $$payload-extension             | Section |
    |                     |                                 | 2.9.3   |
    +---------------------+---------------------------------+---------+
    | evidence-entry      | $$evidence-extension            | Section |
    |                     |                                 | 2.9.4   |
    +---------------------+---------------------------------+---------+

                Table 1: CoSWID CDDL Group Extension Points

   The CoSWID Items Registry defined in Section 6.1 provides a
   registration mechanism allowing new items, and their associated index
   values, to be added to the CoSWID model through the use of the CDDL
   sockets described in the table above.  This registration mechanism
   provides for well-known index values for data items in CoSWID
   extensions, allowing these index values to be recognized by
   implementations supporting a given extension.




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   The following additional CDDL sockets are defined in this document to
   allow for adding new values to corresponding type-choices (i.e. to
   represent enumerations) via custom CDDL specifications.

           +==================+=================+=============+
           | Enumeration Name | CDDL Socket     | Defined in  |
           +==================+=================+=============+
           | version-scheme   | $version-scheme | Section 4.1 |
           +------------------+-----------------+-------------+
           | role             | $role           | Section 4.2 |
           +------------------+-----------------+-------------+
           | ownership        | $ownership      | Section 4.3 |
           +------------------+-----------------+-------------+
           | rel              | $rel            | Section 4.4 |
           +------------------+-----------------+-------------+
           | use              | $use            | Section 4.5 |
           +------------------+-----------------+-------------+

            Table 2: CoSWID CDDL Enumeration Extension Points

   A number of CoSWID value registries are also defined in Section 6.2
   that allow new values to be registered with IANA for the enumerations
   above.  This registration mechanism supports the definition of new
   well-known index values and names for new enumeration values used by
   CoSWID, which can also be used by other software tagging
   specifications.  This registration mechanism allows new standardized
   enumerated values to be shared between multiple tagging
   specifications (and associated implementations) over time.

2.3.  The concise-swid-tag Map

   The CDDL specification for the root concise-swid-tag map is as
   follows and this rule and its constraints MUST be followed when
   creating or validating a CoSWID tag:

















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   concise-swid-tag = {
     tag-id => text / bstr .size 16,
     tag-version => integer,
     ? corpus => bool,
     ? patch => bool,
     ? supplemental => bool,
     software-name => text,
     ? software-version => text,
     ? version-scheme => $version-scheme,
     ? media => text,
     ? software-meta => one-or-more<software-meta-entry>,
     entity => one-or-more<entity-entry>,
     ? link => one-or-more<link-entry>,
     ? payload-or-evidence,
     * $$coswid-extension,
     global-attributes,
   }

   payload-or-evidence //= ( payload => payload-entry )
   payload-or-evidence //= ( evidence => evidence-entry )

   tag-id = 0
   software-name = 1
   entity = 2
   evidence = 3
   link = 4
   software-meta = 5
   payload = 6
   corpus = 8
   patch = 9
   media = 10
   supplemental = 11
   tag-version = 12
   software-version = 13
   version-scheme = 14

   $version-scheme /= multipartnumeric
   $version-scheme /= multipartnumeric-suffix
   $version-scheme /= alphanumeric
   $version-scheme /= decimal
   $version-scheme /= semver
   $version-scheme /= int / text
   multipartnumeric = 1
   multipartnumeric-suffix = 2
   alphanumeric = 3
   decimal = 4
   semver = 16384




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   The following describes each member of the concise-swid-tag root map.

   *  global-attributes: A list of items including an optional language
      definition to support the processing of text-string values and an
      unbounded set of any-attribute items.  Described in Section 2.5.

   *  tag-id (index 0): A 16-byte binary string, or a textual
      identifier, uniquely referencing a software component.  The tag
      identifier MUST be globally unique.  Failure to ensure global
      uniqueness can create ambiguity in tag use since the tag-id serves
      as the global key for matching and lookups.  If represented as a
      16-byte binary string, the identifier MUST be a valid universally
      unique identifier as defined by [RFC4122].  There are no strict
      guidelines on how the identifier is structured, but examples
      include a 16-byte GUID (e.g., class 4 UUID) [RFC4122], or a DNS
      domain name followed by a "/" and a text string, where the domain
      name serves to ensure uniqueness across organizations.  A textual
      tag-id MUST NOT contain a sequence of two underscores ("__", see
      Section 6.7).

   *  tag-version (index 12): An integer value that indicate the
      specific release revision of the tag.  Typically, the initial
      value of this field is set to 0 and the value is increased for
      subsequent tags produced for the same software component release.
      This value allows a CoSWID tag producer to correct an incorrect
      tag previously released without indicating a change to the
      underlying software component the tag represents.  For example,
      the tag version could be changed to add new metadata, to correct a
      broken link, to add a missing payload entry, etc.  When producing
      a revised tag, the new tag-version value MUST be greater than the
      old tag-version value.

   *  corpus (index 8): A boolean value that indicates if the tag
      identifies and describes an installable software component in its
      pre-installation state.  Installable software includes an
      installation package or installer for a software component, a
      software update, or a patch.  If the CoSWID tag represents
      installable software, the corpus item MUST be set to "true".  If
      not provided, the default value MUST be considered "false".

   *  patch (index 9): A boolean value that indicates if the tag
      identifies and describes an installed patch that has made
      incremental changes to a software component installed on an
      endpoint.  If a CoSWID tag is for a patch, the patch item MUST be
      set to "true".  If not provided, the default value MUST be
      considered "false".  A patch item's value MUST NOT be set to
      "true" if the installation of the associated software package
      changes the version of a software component.



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   *  supplemental (index 11): A boolean value that indicates if the tag
      is providing additional information to be associated with another
      referenced SWID or CoSWID tag.  This allows tools and users to
      record their own metadata about a software component without
      modifying SWID primary or patch tags created by a software
      provider.  If a CoSWID tag is a supplemental tag, the supplemental
      item MUST be set to "true".  If not provided, the default value
      MUST be considered "false".

   *  software-name (index 1): This textual item provides the software
      component's name.  This name is likely the same name that would
      appear in a package management tool.  This item maps to
      '/SoftwareIdentity/@name' in [SWID].

   *  software-version (index 13): A textual value representing the
      specific release or development version of the software component.
      This item maps to '/SoftwareIdentity/@version' in [SWID].

   *  version-scheme (index 14): An integer or textual value
      representing the versioning scheme used for the software-version
      item, as an integer label with text escape (Section 2, for the
      "Version Scheme" registry Section 4.1).  If an integer value is
      used it MUST be an index value in the range -256 to 65535.
      Integer values in the range -256 to -1 are reserved for testing
      and use in closed environments (see Section 6.2.2).  Integer
      values in the range 0 to 65535 correspond to registered entries in
      the IANA "Software ID Version Scheme Values" registry (see
      Section 6.2.4).

   *  media (index 10): This text value is a hint to the tag consumer to
      understand what target platform this tag applies to.  This item
      MUST be formatted as a query as defined by the W3C Media Queries
      Recommendation (see [W3C.REC-css3-mediaqueries-20120619]).
      Support for media queries are included here for interoperability
      with [SWID], which does not provide any further requirements for
      media query use.  Thus, this specification does not clarify how a
      media query is to be used for a CoSWID.

   *  software-meta (index 5): An open-ended map of key/value data
      pairs.  A number of predefined keys can be used within this item
      providing for common usage and semantics across the industry.  Use
      of this map allows any additional attribute to be included in the
      tag.  It is expected that industry groups will use a common set of
      attribute names to allow for interoperability within their
      communities.  Described in Section 2.8.  This item maps to
      '/SoftwareIdentity/Meta' in [SWID].





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   *  entity (index 2): Provides information about one or more
      organizations responsible for producing the CoSWID tag, and
      producing or releasing the software component referenced by this
      CoSWID tag.  Described in Section 2.6.

   *  link (index 4): Provides a means to establish relationship arcs
      between the tag and another items.  A given link can be used to
      establish the relationship between tags or to reference another
      resource that is related to the CoSWID tag, e.g., vulnerability
      database association, ROLIE feed [RFC8322], MUD resource
      [RFC8520], software download location, etc).  This is modeled
      after the HTML "link" element.  Described in Section 2.7.

   *  payload (index 6): This item represents a collection of software
      artifacts (described by child items) that compose the target
      software.  For example, these artifacts could be the files
      included with an installer for a corpus tag or installed on an
      endpoint when the software component is installed for a primary or
      patch tag.  The artifacts listed in a payload may be a superset of
      the software artifacts that are actually installed.  Based on user
      selections at install time, an installation might not include
      every artifact that could be created or executed on the endpoint
      when the software component is installed or run.  This item is
      mutually exclusive to evidence, as payload can only be provided by
      an external entity.  Described in Section 2.9.3.

   *  evidence (index 3): This item can be used to record the results of
      a software discovery process used to identify untagged software on
      an endpoint or to represent indicators for why software is
      believed to be installed on the endpoint.  In either case, a
      CoSWID tag can be created by the tool performing an analysis of
      the software components installed on the endpoint.  This item is
      mutually exclusive to payload, as evidence is always generated on
      the target device ad-hoc.  Described in Section 2.9.4.

   *  $$coswid-extension: This CDDL socket is used to add new
      information structures to the concise-swid-tag root map.  See
      Section 2.2.

2.4.  concise-swid-tag Co-Constraints

   The following co-constraints apply to the information provided in the
   concise-swid-tag group.

   *  The patch and supplemental items MUST NOT both be set to "true".






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   *  If the patch item is set to "true", the tag MUST contain at least
      one link item (see Section 2.7) with both the rel item value of
      "patches" and an href item specifying an association with the
      software that was patched.  Without at least one link item the
      target of the patch cannot be identified and the patch tag cannot
      be applied without external context.

   *  If all of the corpus, patch, and supplemental items are "false",
      or if the corpus item is set to "true", then a software-version
      item MUST be included with a value set to the version of the
      software component.  This ensures that primary and corpus tags
      have an identifiable software version.

2.5.  The global-attributes Group

   The global-attributes group provides a list of items, including an
   optional language definition to support the processing of text-string
   values, and an unbounded set of any-attribute items allowing for
   additional items to be provided as a general point of extension in
   the model.

   The CDDL for the global-attributes follows:

   global-attributes = (
     ? lang => text,
     * any-attribute,
   )

   any-attribute = (
     label => one-or-more<text> / one-or-more<int>
   )

   label = text / int

   The following describes each child item of this group.

   *  lang (index 15): A textual language tag that conforms with IANA
      "Language Subtag Registry" [RFC5646].  The context of the
      specified language applies to all sibling and descendant textual
      values, unless a descendant object has defined a different
      language tag.  Thus, a new context is established when a
      descendant object redefines a new language tag.  All textual
      values within a given context MUST be considered expressed in the
      specified language.







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   *  any-attribute: This sub-group provides a means to include
      arbitrary information via label/index ("key") value pairs.  Labels
      can be either a single integer or text string.  Values can be a
      single integer, a text string, or an array of integers or text
      strings.

2.6.  The entity-entry Map

   The CDDL for the entity-entry map follows:

   entity-entry = {
     entity-name => text,
     ? reg-id => any-uri,
     role => one-or-more<$role>,
     ? thumbprint => hash-entry,
     * $$entity-extension,
     global-attributes,
   }

   entity-name = 31
   reg-id = 32
   role = 33
   thumbprint = 34

   $role /= tag-creator
   $role /= software-creator
   $role /= aggregator
   $role /= distributor
   $role /= licensor
   $role /= maintainer
   $role /= int / text
   tag-creator=1
   software-creator=2
   aggregator=3
   distributor=4
   licensor=5
   maintainer=6

   The following describes each child item of this group.

   *  global-attributes: The global-attributes group described in
      Section 2.5.

   *  entity-name (index 31): The textual name of the organizational
      entity claiming the roles specified by the role item for the
      CoSWID tag.  This item maps to '/SoftwareIdentity/Entity/@name' in
      [SWID].




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   *  reg-id (index 32): The registration id value is intended to
      uniquely identify a naming authority in a given scope (e.g.,
      global, organization, vendor, customer, administrative domain,
      etc.) for the referenced entity.  The value of a registration ID
      MUST be a RFC 3986 URI; it is not intended to be dereferenced.
      The scope will usually be the scope of an organization.

   *  role (index 33): An integer or textual value (integer label with
      text escape, see Section 2) representing the relationship(s)
      between the entity, and this tag or the referenced software
      component.  If an integer value is used it MUST be an index value
      in the range -256 to 255.  Integer values in the range -256 to -1
      are reserved for testing and use in closed environments (see
      Section 6.2.2).  Integer values in the range 0 to 255 correspond
      to registered entries in the IANA "Software ID Entity Role Values"
      registry (see Section 6.2.5).

      The following additional requirements exist for the use of the
      "role" item:

      -  An entity item MUST be provided with the role of "tag-creator"
         for every CoSWID tag.  This indicates the organization that
         created the CoSWID tag.

      -  An entity item SHOULD be provided with the role of "software-
         creator" for every CoSWID tag, if this information is known to
         the tag creator.  This indicates the organization that created
         the referenced software component.

   *  thumbprint (index 34): The value of the thumbprint item provides a
      hash (i.e. the thumbprint) of the signing entity's public key
      certificate.  This provides an indicator of which entity signed
      the CoSWID tag, which will typically be the tag creator.  See
      Section 2.9.1 for more details on the use of the hash-entry data
      structure.

   *  $$entity-extension: This CDDL socket can be used to extend the
      entity-entry group model.  See Section 2.2.

2.7.  The link-entry Map

   The CDDL for the link-entry map follows:









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   link-entry = {
     ? artifact => text,
     href => any-uri,
     ? media => text,
     ? ownership => $ownership,
     rel => $rel,
     ? media-type => text,
     ? use => $use,
     * $$link-extension,
     global-attributes,
   }

   media = 10
   artifact = 37
   href = 38
   ownership = 39
   rel = 40
   media-type = 41
   use = 42

   $ownership /= shared
   $ownership /= private
   $ownership /= abandon
   $ownership /= int / text
   abandon=1
   private=2
   shared=3

   $rel /= ancestor
   $rel /= component
   $rel /= feature
   $rel /= installationmedia
   $rel /= packageinstaller
   $rel /= parent
   $rel /= patches
   $rel /= requires
   $rel /= see-also
   $rel /= supersedes
   $rel /= supplemental
   $rel /= -356..65536 / text
   ancestor=1
   component=2
   feature=3
   installationmedia=4
   packageinstaller=5
   parent=6
   patches=7
   requires=8



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   see-also=9
   supersedes=10
   supplemental=11

   $use /= optional
   $use /= required
   $use /= recommended
   $use /= int / text
   optional=1
   required=2
   recommended=3

   The following describes each member of this map.

   *  global-attributes: The global-attributes group described in
      Section 2.5.

   *  artifact (index 37): To be used with rel="installationmedia", this
      item's value provides the absolute filesystem path to the
      installer executable or script that can be run to launch the
      referenced installation.  Links with the same artifact name MUST
      be considered mirrors of each other, allowing the installation
      media to be acquired from any of the described sources.

   *  href (index 38): A URI-reference [RFC3986] for the referenced
      resource.  The "href" item's value can be, but is not limited to,
      the following (which is a slightly modified excerpt from [SWID]):

      -  If no URI scheme is provided, then the URI-reference is a
         relative reference relative to the base URI of the CoSWID tag,
         i.e., the URI under which the CoSWID tag was provided.  For
         example, "./folder/supplemental.coswid".

      -  a physical resource location with any acceptable URI scheme
         (e.g., file:// http:// https:// ftp://)

      -  a URI with "swid:" as the scheme refers to another SWID or
         CoSWID by the referenced tag's tag-id.  This URI needs to be
         resolved in the context of the endpoint by software that can
         lookup other SWID or CoSWID tags.  For example, "swid:2df9de35-
         0aff-4a86-ace6-f7dddd1ade4c" references the tag with the tag-id
         value "2df9de35-0aff-4a86-ace6-f7dddd1ade4c".









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      -  a URI with "swidpath:" as the scheme, which refers to another
         software tag via an XPATH query [W3C.REC-xpath20-20101214] that
         matches items in that tag (Section 5.2).  This scheme is
         provided for compatibility with [SWID].  This specification
         does not define how to resolve an XPATH query in the context of
         CBOR, see Section 5.2.

   *  media (index 10): A hint to the consumer of the link to what
      target platform the link is applicable to.  This item represents a
      query as defined by the W3C Media Queries Recommendation (see
      [W3C.REC-css3-mediaqueries-20120619]).  As highlighted in media
      defined in Section 2.3, support for media queries are included
      here for interoperability with [SWID], which does not provide any
      further requirements for media query use.  Thus, this
      specification does not clarify how a media query is to be used for
      a CoSWID.

   *  ownership (index 39): An integer or textual value (integer label
      with text escape, see Section 2, for the "Software ID Link
      Ownership Values" registry Section 4.3) used when the "href" item
      references another software component to indicate the degree of
      ownership between the software component referenced by the CoSWID
      tag and the software component referenced by the link.  If an
      integer value is used it MUST be an index value in the range -256
      to 255.  Integer values in the range -256 to -1 are reserved for
      testing and use in closed environments (see Section 6.2.2).
      Integer values in the range 0 to 255 correspond to registered
      entries in the "Software ID Link Ownership Values" registry.























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   *  rel (index 40): An integer or textual value that (integer label
      with text escape, see Section 2, for the "Software ID Link Link
      Relationship Values" registry Section 4.3) identifies the
      relationship between this CoSWID and the target resource
      identified by the "href" item.  If an integer value is used it
      MUST be an index value in the range -256 to 65535.  Integer values
      in the range -256 to -1 are reserved for testing and use in closed
      environments (see Section 6.2.2).  Integer values in the range 0
      to 65535 correspond to registered entries in the IANA "Software ID
      Link Relationship Values" registry (see Section 6.2.7).  If a
      string value is used it MUST be either a private use name as
      defined in Section 6.2.2 or a "Relation Name" from the IANA "Link
      Relation Types" registry: https://www.iana.org/assignments/link-
      relations/link-relations.xhtml as defined by [RFC8288].  When a
      string value defined in the IANA "Software ID Link Relationship
      Values" registry matches a Relation Name defined in the IANA "Link
      Relation Types" registry, the index value in the IANA "Software ID
      Link Relationship Values" registry MUST be used instead, as this
      relationship has a specialized meaning in the context of a CoSWID
      tag.  String values correspond to registered entries in the
      "Software ID Link Relationship Values" registry.

   *  media-type (index 41): A link can point to arbitrary resources on
      the endpoint, local network, or Internet using the href item.  Use
      of this item supplies the resource consumer with a hint of what
      type of resource to expect.  (This is a _hint_: There is no
      obligation for the server hosting the target of the URI to use the
      indicated media type when the URI is dereferenced.)  Media types
      are identified by referencing a "Name" from the IANA "Media Types"
      registry: http://www.iana.org/assignments/media-types/media-
      types.xhtml.  This item maps to '/SoftwareIdentity/Link/@type' in
      [SWID].

   *  use (index 42): An integer or textual value (integer label with
      text escape, see Section 2, for the "Software ID Link Link
      Relationship Values" registry Section 4.3) used to determine if
      the referenced software component has to be installed before
      installing the software component identified by the COSWID tag.
      If an integer value is used it MUST be an index value in the range
      -256 to 255.  Integer values in the range -256 to -1 are reserved
      for testing and use in closed environments (see Section 6.2.2).
      Integer values in the range 0 to 255 correspond to registered
      entries in the IANA "Link Use Values" registry (see
      Section 6.2.8).  If a string value is used it MUST be a private
      use name as defined in Section 6.2.2.  String values correspond to
      registered entries in the "Software ID Link Use Values" registry.





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   *  $$link-extension: This CDDL socket can be used to extend the link-
      entry map model.  See Section 2.2.

2.8.  The software-meta-entry Map

   The CDDL for the software-meta-entry map follows:

   software-meta-entry = {
     ? activation-status => text,
     ? channel-type => text,
     ? colloquial-version => text,
     ? description => text,
     ? edition => text,
     ? entitlement-data-required => bool,
     ? entitlement-key => text,
     ? generator =>  text / bstr .size 16,
     ? persistent-id => text,
     ? product => text,
     ? product-family => text,
     ? revision => text,
     ? summary => text,
     ? unspsc-code => text,
     ? unspsc-version => text,
     * $$software-meta-extension,
     global-attributes,
   }

   activation-status = 43
   channel-type = 44
   colloquial-version = 45
   description = 46
   edition = 47
   entitlement-data-required = 48
   entitlement-key = 49
   generator = 50
   persistent-id = 51
   product = 52
   product-family = 53
   revision = 54
   summary = 55
   unspsc-code = 56
   unspsc-version = 57

   The following describes each child item of this group.

   *  global-attributes: The global-attributes group described in
      Section 2.5.




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   *  activation-status (index 43): A textual value that identifies how
      the software component has been activated, which might relate to
      specific terms and conditions for its use (e.g., Trial,
      Serialized, Licensed, Unlicensed, etc) and relate to an
      entitlement.  This attribute is typically used in supplemental
      tags as it contains information that might be selected during a
      specific install.

   *  channel-type (index 44): A textual value that identifies which
      sales, licensing, or marketing channel the software component has
      been targeted for (e.g., Volume, Retail, OEM, Academic, etc).
      This attribute is typically used in supplemental tags as it
      contains information that might be selected during a specific
      install.

   *  colloquial-version (index 45): A textual value for the software
      component's informal or colloquial version.  Examples may include
      a year value, a major version number, or similar value that are
      used to identify a group of specific software component releases
      that are part of the same release/support cycle.  This version can
      be the same through multiple releases of a software component,
      while the software-version specified in the concise-swid-tag group
      is much more specific and will change for each software component
      release.  This version is intended to be used for string
      comparison (byte-by-byte) only and is not intended to be used to
      determine if a specific value is earlier or later in a sequence.

   *  description (index 46): A textual value that provides a detailed
      description of the software component.  This value MAY be multiple
      paragraphs separated by CR LF characters as described by
      [RFC5198].

   *  edition (index 47): A textual value indicating that the software
      component represents a functional variation of the code base used
      to support multiple software components.  For example, this item
      can be used to differentiate enterprise, standard, or professional
      variants of a software component.

   *  entitlement-data-required (index 48): A boolean value that can be
      used to determine if accompanying proof of entitlement is needed
      when a software license reconciliation process is performed.

   *  entitlement-key (index 49): A vendor-specific textual key that can
      be used to identify and establish a relationship to an
      entitlement.  Examples of an entitlement-key might include a
      serial number, product key, or license key.  For values that
      relate to a given software component install (i.e., license key),
      a supplemental tag will typically contain this information.  In



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      other cases, where a general-purpose key can be provided that
      applies to all possible installs of the software component on
      different endpoints, a primary tag will typically contain this
      information.  Since CoSWID tags are not intended to contain
      confidential information, tag authors are advised not to record
      unprotected, private software license keys in this field.

   *  generator (index 50): The name (or tag-id) of the software
      component that created the CoSWID tag.  If the generating software
      component has a SWID or CoSWID tag, then the tag-id for the
      generating software component SHOULD be provided.

   *  persistent-id (index 51): A globally unique identifier used to
      identify a set of software components that are related.  Software
      components sharing the same persistent-id can be different
      versions.  This item can be used to relate software components,
      released at different points in time or through different release
      channels, that may not be able to be related through use of the
      link item.

   *  product (index 52): A basic name for the software component that
      can be common across multiple tagged software components (e.g.,
      Apache HTTPD).

   *  product-family (index 53): A textual value indicating the software
      components overall product family.  This should be used when
      multiple related software components form a larger capability that
      is installed on multiple different endpoints.  For example, some
      software families may consist of server, client, and shared
      service components that are part of a larger capability.  Email
      systems, enterprise applications, backup services, web
      conferencing, and similar capabilities are examples of families.
      Use of this item is not intended to represent groups of software
      that are bundled or installed together.  The persistent-id or link
      items SHOULD be used to relate bundled software components.

   *  revision (index 54): A string value indicating an informal or
      colloquial release version of the software.  This value can
      provide a different version value as compared to the software-
      version specified in the concise-swid-tag group.  This is useful
      when one or more releases need to have an informal version label
      that differs from the specific exact version value specified by
      software-version.  Examples can include SP1, RC1, Beta, etc.

   *  summary (index 55): A short description of the software component.
      This MUST be a single sentence suitable for display in a user
      interface.




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   *  unspsc-code (index 56): An 8 digit UNSPSC classification code for
      the software component as defined by the United Nations Standard
      Products and Services Code (UNSPSC, [UNSPSC]).

   *  unspsc-version (index 57): The version of UNSPSC used to define
      the unspsc-code value.

   *  $$meta-extension: This CDDL socket can be used to extend the
      software-meta-entry group model.  See Section 2.2.

2.9.  The Resource Collection Definition

2.9.1.  The hash-entry Array

   CoSWID adds explicit support for the representation of hash entries
   using algorithms that are registered in the IANA "Named Information
   Hash Algorithm Registry" [IANA.named-information] using the hash
   member (index 7) and the corresponding hash-entry type.  This is the
   equivalent of the namespace qualified "hash" attribute in [SWID].

   hash-entry = [
     hash-alg-id: int,
     hash-value: bytes,
   ]

   The number used as a value for hash-alg-id is an integer-based hash
   algorithm identifier who's value MUST refer to an ID in the IANA
   "Named Information Hash Algorithm Registry" [IANA.named-information]
   with a Status of "current" (at the time the generator software was
   built or later); other hash algorithms MUST NOT be used.  If the
   hash-alg-id is not known, then the integer value "0" MUST be used.
   This allows for conversion from ISO SWID tags [SWID], which do not
   allow an algorithm to be identified for this field.

   The hash-value MUST represent the raw hash value as a byte string (as
   opposed to, e.g., base64 encoded) generated from the representation
   of the resource using the hash algorithm indicated by hash-alg-id.

2.9.2.  The resource-collection Group

   A list of items both used in evidence (created by a software
   discovery process) and payload (installed in an endpoint) content of
   a CoSWID tag document to structure and differentiate the content of
   specific CoSWID tag types.  Potential content includes directories,
   files, processes, or resources.

   The CDDL for the resource-collection group follows:




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   path-elements-group = ( ? directory => one-or-more<directory-entry>,
                           ? file => one-or-more<file-entry>,
                         )

   resource-collection = (
     path-elements-group,
     ? process => one-or-more<process-entry>,
     ? resource => one-or-more<resource-entry>,
     * $$resource-collection-extension,
   )

   filesystem-item = (
     ? key => bool,
     ? location => text,
     fs-name => text,
     ? root => text,
   )

   file-entry = {
     filesystem-item,
     ? size => uint,
     ? file-version => text,
     ? hash => hash-entry,
     * $$file-extension,
     global-attributes,
   }

   directory-entry = {
     filesystem-item,
     ? path-elements => { path-elements-group },
     * $$directory-extension,
     global-attributes,
   }

   process-entry = {
     process-name => text,
     ? pid => integer,
     * $$process-extension,
     global-attributes,
   }

   resource-entry = {
     type => text,
     * $$resource-extension,
     global-attributes,
   }

   directory = 16



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   file = 17
   process = 18
   resource = 19
   size = 20
   file-version = 21
   key = 22
   location = 23
   fs-name = 24
   root = 25
   path-elements = 26
   process-name = 27
   pid = 28
   type = 29

   The following describes each member of the groups and maps
   illustrated above.

   *  filesystem-item: A list of common items used for representing the
      filesystem root, relative location, name, and significance of a
      file or directory item.

   *  global-attributes: The global-attributes group described in
      Section 2.5.

   *  directory (index 16): A directory item allows child directory and
      file items to be defined within a directory hierarchy for the
      software component.

   *  file (index 17): A file item allows details about a file to be
      provided for the software component.

   *  process (index 18): A process item allows details to be provided
      about the runtime behavior of the software component, such as
      information that will appear in a process listing on an endpoint.

   *  resource (index 19): A resource item can be used to provide
      details about an artifact or capability expected to be found on an
      endpoint or evidence collected related to the software component.
      This can be used to represent concepts not addressed directly by
      the directory, file, or process items.  Examples include: registry
      keys, bound ports, etc.  The equivalent construct in [SWID] is
      currently under specified.  As a result, this item might be
      further defined through extension in the future.

   *  size (index 20): The file's size in bytes.






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   *  file-version (index 21): The file's version as reported by
      querying information on the file from the operating system (if
      available).  This item maps to
      '/SoftwareIdentity/(Payload|Evidence)/File/@version' in [SWID].

   *  hash (index 7): A hash of the file as described in Section 2.9.1.

   *  key (index 22): A boolean value indicating if a file or directory
      is significant or required for the software component to execute
      or function properly.  These are files or directories that can be
      used to affirmatively determine if the software component is
      installed on an endpoint.

   *  location (index 23): The filesystem path where a file is expected
      to be located when installed or copied.  The location MUST be
      either relative to the location of the parent directory item
      (preferred), or relative to the location of the CoSWID tag (as
      indicated in the location value in the evidence entry map) if no
      parent is defined.  The location MUST NOT include a file's name,
      which is provided by the fs-name item.

   *  fs-name (index 24): The name of the directory or file without any
      path information.  This aligns with a file "name" in [SWID].  This
      item maps to
      '/SoftwareIdentity/(Payload|Evidence)/(File|Directory)/@name' in
      [SWID].

   *  root (index 25): A host-specific name for the root of the
      filesystem.  The location item is considered relative to this
      location if specified.  If not provided, the value provided by the
      location item is expected to be relative to its parent or the
      location of the CoSWID tag if no parent is provided.

   *  path-elements (index 26): This group allows a hierarchy of
      directory and file items to be defined in payload or evidence
      items.  This is a construction within the CDDL definition of
      CoSWID to support shared syntax and does not appear in [SWID].

   *  process-name (index 27): The software component's process name as
      it will appear in an endpoint's process list.  This aligns with a
      process "name" in [SWID].  This item maps to
      '/SoftwareIdentity/(Payload|Evidence)/Process/@name' in [SWID].

   *  pid (index 28): The process ID identified for a running instance
      of the software component in the endpoint's process list.  This is
      used as part of the evidence item.





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   *  type (index 29): A human-readable string indicating the type of
      resource.

   *  $$resource-collection-extension: This CDDL socket can be used to
      extend the resource-collection group model.  This can be used to
      add new specialized types of resources.  See Section 2.2.

   *  $$file-extension: This CDDL socket can be used to extend the file-
      entry group model.  See Section 2.2.

   *  $$directory-extension: This CDDL socket can be used to extend the
      directory-entry group model.  See Section 2.2.

   *  $$process-extension: This CDDL socket can be used to extend the
      process-entry group model.  See Section 2.2.

   *  $$resource-extension: This CDDL socket can be used to extend the
      resource-entry group model.  See Section 2.2.

2.9.3.  The payload-entry Map

   The CDDL for the payload-entry map follows:

   payload-entry = {
     resource-collection,
     * $$payload-extension,
     global-attributes,
   }

   The following describes each child item of this group.

   *  global-attributes: The global-attributes group described in
      Section 2.5.

   *  resource-collection: The resource-collection group described in
      Section 2.9.2.

   *  $$payload-extension: This CDDL socket can be used to extend the
      payload-entry group model.  See Section 2.2.

2.9.4.  The evidence-entry Map

   The CDDL for the evidence-entry map follows:








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   evidence-entry = {
     resource-collection,
     ? date => integer-time,
     ? device-id => text,
     ? location => text,
     * $$evidence-extension,
     global-attributes,
   }

   date = 35
   device-id = 36

   The following describes each child item of this group.

   *  global-attributes: The global-attributes group described in
      Section 2.5.

   *  resource-collection: The resource-collection group described in
      Section 2.9.2.

   *  date (index 35): The date and time the information was collected
      pertaining to the evidence item in Epoch-Based Date/Time format as
      specified in Section 3.4.2 of [RFC8949].

   *  device-id (index 36): The endpoint's string identifier from which
      the evidence was collected.

   *  location (index 23): The absolute filepath of the location of the
      CoSWID tag generated as evidence.  (Location values in filesystem-
      items in the payload can be expressed relative to this location.)

   *  $$evidence-extension: This CDDL socket can be used to extend the
      evidence-entry group model.  See Section 2.2.

2.10.  Full CDDL Specification

   In order to create a valid CoSWID document the structure of the
   corresponding CBOR message MUST adhere to the following CDDL
   specification.

   <CODE BEGINS>
   concise-swid-tag = {
     tag-id => text / bstr .size 16,
     tag-version => integer,
     ? corpus => bool,
     ? patch => bool,
     ? supplemental => bool,
     software-name => text,



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     ? software-version => text,
     ? version-scheme => $version-scheme,
     ? media => text,
     ? software-meta => one-or-more<software-meta-entry>,
     entity => one-or-more<entity-entry>,
     ? link => one-or-more<link-entry>,
     ? payload-or-evidence,
     * $$coswid-extension,
     global-attributes,
   }

   payload-or-evidence //= ( payload => payload-entry )
   payload-or-evidence //= ( evidence => evidence-entry )

   any-uri = uri
   label = text / int

   $version-scheme /= multipartnumeric
   $version-scheme /= multipartnumeric-suffix
   $version-scheme /= alphanumeric
   $version-scheme /= decimal
   $version-scheme /= semver
   $version-scheme /= int / text

   any-attribute = (
     label => one-or-more<text> / one-or-more<int>
   )

   one-or-more<T> = T / [ 2* T ]

   global-attributes = (
     ? lang => text,
     * any-attribute,
   )

   hash-entry = [
     hash-alg-id: int,
     hash-value: bytes,
   ]

   entity-entry = {
     entity-name => text,
     ? reg-id => any-uri,
     role => one-or-more<$role>,
     ? thumbprint => hash-entry,
     * $$entity-extension,
     global-attributes,
   }



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   $role /= tag-creator
   $role /= software-creator
   $role /= aggregator
   $role /= distributor
   $role /= licensor
   $role /= maintainer
   $role /= int / text

   link-entry = {
     ? artifact => text,
     href => any-uri,
     ? media => text,
     ? ownership => $ownership,
     rel => $rel,
     ? media-type => text,
     ? use => $use,
     * $$link-extension,
     global-attributes,
   }

   $ownership /= shared
   $ownership /= private
   $ownership /= abandon
   $ownership /= int / text

   $rel /= ancestor
   $rel /= component
   $rel /= feature
   $rel /= installationmedia
   $rel /= packageinstaller
   $rel /= parent
   $rel /= patches
   $rel /= requires
   $rel /= see-also
   $rel /= supersedes
   $rel /= supplemental
   $rel /= -256..64436 / text

   $use /= optional
   $use /= required
   $use /= recommended
   $use /= int / text

   software-meta-entry = {
     ? activation-status => text,
     ? channel-type => text,
     ? colloquial-version => text,
     ? description => text,



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     ? edition => text,
     ? entitlement-data-required => bool,
     ? entitlement-key => text,
     ? generator =>  text / bstr .size 16,
     ? persistent-id => text,
     ? product => text,
     ? product-family => text,
     ? revision => text,
     ? summary => text,
     ? unspsc-code => text,
     ? unspsc-version => text,
     * $$software-meta-extension,
     global-attributes,
   }

   path-elements-group = ( ? directory => one-or-more<directory-entry>,
                           ? file => one-or-more<file-entry>,
                         )

   resource-collection = (
     path-elements-group,
     ? process => one-or-more<process-entry>,
     ? resource => one-or-more<resource-entry>,
     * $$resource-collection-extension,
   )

   file-entry = {
     filesystem-item,
     ? size => uint,
     ? file-version => text,
     ? hash => hash-entry,
     * $$file-extension,
     global-attributes,
   }

   directory-entry = {
     filesystem-item,
     ? path-elements => { path-elements-group },
     * $$directory-extension,
     global-attributes,
   }

   process-entry = {
     process-name => text,
     ? pid => integer,
     * $$process-extension,
     global-attributes,
   }



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   resource-entry = {
     type => text,
     * $$resource-extension,
     global-attributes,
   }

   filesystem-item = (
     ? key => bool,
     ? location => text,
     fs-name => text,
     ? root => text,
   )

   payload-entry = {
     resource-collection,
     * $$payload-extension,
     global-attributes,
   }

   evidence-entry = {
     resource-collection,
     ? date => integer-time,
     ? device-id => text,
     ? location => text,
     * $$evidence-extension,
     global-attributes,
   }

   integer-time = #6.1(int)

   ; "global map member" integer indexes
   tag-id = 0
   software-name = 1
   entity = 2
   evidence = 3
   link = 4
   software-meta = 5
   payload = 6
   hash = 7
   corpus = 8
   patch = 9
   media = 10
   supplemental = 11
   tag-version = 12
   software-version = 13
   version-scheme = 14
   lang = 15
   directory = 16



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   file = 17
   process = 18
   resource = 19
   size = 20
   file-version = 21
   key = 22
   location = 23
   fs-name = 24
   root = 25
   path-elements = 26
   process-name = 27
   pid = 28
   type = 29
   entity-name = 31
   reg-id = 32
   role = 33
   thumbprint = 34
   date = 35
   device-id = 36
   artifact = 37
   href = 38
   ownership = 39
   rel = 40
   media-type = 41
   use = 42
   activation-status = 43
   channel-type = 44
   colloquial-version = 45
   description = 46
   edition = 47
   entitlement-data-required = 48
   entitlement-key = 49
   generator = 50
   persistent-id = 51
   product = 52
   product-family = 53
   revision = 54
   summary = 55
   unspsc-code = 56
   unspsc-version = 57

   ; "version-scheme" integer indexes
   multipartnumeric = 1
   multipartnumeric-suffix = 2
   alphanumeric = 3
   decimal = 4
   semver = 16384




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   ; "role" integer indexes
   tag-creator=1
   software-creator=2
   aggregator=3
   distributor=4
   licensor=5
   maintainer=6

   ; "ownership" integer indexes
   abandon=1
   private=2
   shared=3

   ; "rel" integer indexes
   ancestor=1
   component=2
   feature=3
   installationmedia=4
   packageinstaller=5
   parent=6
   patches=7
   requires=8
   see-also=9
   supersedes=10
   ; supplemental=11 ; this is already defined earlier

   ; "use" integer indexes
   optional=1
   required=2
   recommended=3
   <CODE ENDS>

3.  Determining the Type of CoSWID

   The operational model for SWID and CoSWID tags was introduced in
   Section 1.1, which described four different CoSWID tag types.  The
   following additional rules apply to the use of CoSWID tags to ensure
   that created tags properly identify the tag type.

   The first matching rule MUST determine the type of the CoSWID tag.

   1.  Primary Tag: A CoSWID tag MUST be considered a primary tag if the
       corpus, patch, and supplemental items are "false".

   2.  Supplemental Tag: A CoSWID tag MUST be considered a supplemental
       tag if the supplemental item is set to "true".





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   3.  Corpus Tag: A CoSWID tag MUST be considered a corpus tag if the
       corpus item is "true".

   4.  Patch Tag: A CoSWID tag MUST be considered a patch tag if the
       patch item is "true".

   Note: Multiple of the corpus, patch, and supplemental items can have
   values set as "true".  The rules above provide a means to determine
   the tag's type in such a case.  For example, a SWID or CoSWID tag for
   a patch installer might have both corpus and patch items set to
   "true".  In such a case, the tag is a "Corpus Tag".  The tag
   installed by this installer would have only the patch item set to
   "true", making the installed tag type a "Patch Tag".

4.  CoSWID Indexed Label Values

   This section defines a number of kinds of indexed label values that
   are maintained in a registry each (Section 6).  These values are
   represented as positive integers.  In each registry, the value 0 is
   marked as Reserved.

4.1.  Version Scheme

   The following table contains a set of values for use in the concise-
   swid-tag group's version-scheme item.  Version Scheme Name strings
   match the version schemes defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  Index value indicates the value to use as the
   version-scheme item's value.  The Version Scheme Name provides human-
   readable text for the value.  The Definition describes the syntax of
   allowed values for each entry.





















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    +=======+=========================+===============================+
    | Index | Version Scheme Name     | Definition                    |
    +=======+=========================+===============================+
    | 1     | multipartnumeric        | Numbers separated by dots,    |
    |       |                         | where the numbers are         |
    |       |                         | interpreted as decimal        |
    |       |                         | integers (e.g., 1.2.3,        |
    |       |                         | 1.2.3.4.5.6.7, 1.4.5, 1.21)   |
    +-------+-------------------------+-------------------------------+
    | 2     | multipartnumeric+suffix | Numbers separated by dots,    |
    |       |                         | where the numbers are         |
    |       |                         | interpreted as decimal        |
    |       |                         | integers with an additional   |
    |       |                         | textual suffix (e.g., 1.2.3a) |
    +-------+-------------------------+-------------------------------+
    | 3     | alphanumeric            | Strictly a string, no         |
    |       |                         | interpretation as number      |
    +-------+-------------------------+-------------------------------+
    | 4     | decimal                 | A single decimal floating     |
    |       |                         | point number                  |
    +-------+-------------------------+-------------------------------+
    | 16384 | semver                  | A semantic version as defined |
    |       |                         | by [SWID].  Also see the      |
    |       |                         | [SEMVER] specification for    |
    |       |                         | more information              |
    +-------+-------------------------+-------------------------------+

                       Table 3: Version Scheme Values

   multipartnumeric and the numbers part of multipartnumeric+suffix are
   interpreted as a sequence of numbers and are sorted in
   lexicographical order by these numbers (i.e., not by the digits in
   the numbers) and then the textual suffix (for
   multipartnumeric+suffix).  Alphanumeric strings are sorted
   lexicographically as character strings.  Decimal version numbers are
   interpreted as a single floating point number (e.g., 1.25 is less
   than 1.3).

   The values above are registered in the IANA "Software ID Version
   Scheme Values" registry defined in Section 6.2.4.  Additional entries
   will likely be registered over time in this registry.










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   A CoSWID producer that is aware of the version scheme that has been
   used to select the version value, SHOULD include the optional
   version-scheme item to avoid semantic ambiguity.  If the CoSWID
   producer does not have this information, it SHOULD omit the version-
   scheme item.  The following heuristics can be used by a CoSWID
   consumer, based on the version schemes' partially overlapping value
   spaces:

   *  "decimal" and "multipartnumeric" partially overlap in their value
      space when a value matches a decimal number.  When a corresponding
      software-version item's value falls within this overlapping value
      space, it is expected that the "decimal" version scheme is used.

   *  "multipartnumeric" and "semver" partially overlap in their value
      space when a "multipartnumeric" value matches the semantic
      versioning syntax.  When a corresponding software-version item's
      value falls within this overlapping value space, it is expected
      that the "semver" version scheme is used.

   *  "alphanumeric" and other version schemes might overlap in their
      value space.  When a corresponding software-version item's value
      falls within this overlapping value space, it is expected that the
      other version scheme is used and "alphanumeric" is not used.

   Note that these heuristics are imperfect and can guess wrong, which
   is the reason the version-scheme item SHOULD be included by the
   producer.

4.2.  Entity Role Values

   The following table indicates the index value to use for the entity-
   entry group's role item (see Section 2.6).  These values match the
   entity roles defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  The "Index" value indicates the value to use as the
   role item's value.  The "Role Name" provides human-readable text for
   the value.  The "Definition" describes the semantic meaning of each
   entry.














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   +=======+=================+========================================+
   | Index | Role Name       | Definition                             |
   +=======+=================+========================================+
   | 1     | tagCreator      | The person or organization that        |
   |       |                 | created the containing SWID or CoSWID  |
   |       |                 | tag                                    |
   +-------+-----------------+----------------------------------------+
   | 2     | softwareCreator | The person or organization entity that |
   |       |                 | created the software component.        |
   +-------+-----------------+----------------------------------------+
   | 3     | aggregator      | From [SWID], "An organization or       |
   |       |                 | system that encapsulates software from |
   |       |                 | their own and/or other organizations   |
   |       |                 | into a different distribution process  |
   |       |                 | (as in the case of virtualization), or |
   |       |                 | as a completed system to accomplish a  |
   |       |                 | specific task (as in the case of a     |
   |       |                 | value added reseller)."                |
   +-------+-----------------+----------------------------------------+
   | 4     | distributor     | From [SWID], "An entity that furthers  |
   |       |                 | the marketing, selling and/or          |
   |       |                 | distribution of software from the      |
   |       |                 | original place of manufacture to the   |
   |       |                 | ultimate user without modifying the    |
   |       |                 | software, its packaging or its         |
   |       |                 | labelling."                            |
   +-------+-----------------+----------------------------------------+
   | 5     | licensor        | From [SAM] as "software licensor", a   |
   |       |                 | "person or organization who owns or    |
   |       |                 | holds the rights to issue a software   |
   |       |                 | license for a specific software        |
   |       |                 | [component]"                           |
   +-------+-----------------+----------------------------------------+
   | 6     | maintainer      | The person or organization that is     |
   |       |                 | responsible for coordinating and       |
   |       |                 | making updates to the source code for  |
   |       |                 | the software component.  This SHOULD   |
   |       |                 | be used when the "maintainer" is a     |
   |       |                 | different person or organization than  |
   |       |                 | the original "softwareCreator".        |
   +-------+-----------------+----------------------------------------+

                       Table 4: Entity Role Values

   The values above are registered in the IANA "Software ID Entity Role
   Values" registry defined in Section 6.2.5.  Additional values will
   likely be registered over time.




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4.3.  Link Ownership Values

   The following table indicates the index value to use for the link-
   entry group's ownership item (see Section 2.7).  These values match
   the link ownership values defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  The "Index" value indicates the value to use as the
   link-entry group ownership item's value.  The "Ownership Type"
   provides human-readable text for the value.  The "Definition"
   describes the semantic meaning of each entry.

   +=======+===========+===============================================+
   | Index | Ownership | Definition                                    |
   |       | Type      |                                               |
   +=======+===========+===============================================+
   | 1     | abandon   | If the software component referenced by the   |
   |       |           | CoSWID tag is uninstalled, then the           |
   |       |           | referenced software SHOULD NOT be             |
   |       |           | uninstalled                                   |
   +-------+-----------+-----------------------------------------------+
   | 2     | private   | If the software component referenced by the   |
   |       |           | CoSWID tag is uninstalled, then the           |
   |       |           | referenced software SHOULD be uninstalled as  |
   |       |           | well.                                         |
   +-------+-----------+-----------------------------------------------+
   | 3     | shared    | If the software component referenced by the   |
   |       |           | CoSWID tag is uninstalled, then the           |
   |       |           | referenced software SHOULD be uninstalled if  |
   |       |           | no other components sharing the software.     |
   +-------+-----------+-----------------------------------------------+

                       Table 5: Link Ownership Values

   The values above are registered in the IANA "Software ID Link
   Ownership Values" registry defined in Section 6.2.6.  Additional
   values will likely be registered over time.

4.4.  Link Rel Values

   The following table indicates the index value to use for the link-
   entry group's rel item (see Section 2.7).  These values match the
   link rel values defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  The "Index" value indicates the value to use as the
   link-entry group ownership item's value.  The "Relationship Type"
   provides human-readable text for the value.  The "Definition"
   describes the semantic meaning of each entry.






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   +=======+===================+=======================================+
   | Index | Relationship Type | Definition                            |
   +=======+===================+=======================================+
   | 1     | ancestor          | The link references a software        |
   |       |                   | tag for a previous release of         |
   |       |                   | this software.  This can be           |
   |       |                   | useful to define an upgrade path.     |
   +-------+-------------------+---------------------------------------+
   | 2     | component         | The link references a software        |
   |       |                   | tag for a separate component of       |
   |       |                   | this software.                        |
   +-------+-------------------+---------------------------------------+
   | 3     | feature           | The link references a                 |
   |       |                   | configurable feature of this          |
   |       |                   | software that can be enabled or       |
   |       |                   | disabled without changing the         |
   |       |                   | installed files.                      |
   +-------+-------------------+---------------------------------------+
   | 4     | installationmedia | The link references the               |
   |       |                   | installation package that can be      |
   |       |                   | used to install this software.        |
   +-------+-------------------+---------------------------------------+
   | 5     | packageinstaller  | The link references the               |
   |       |                   | installation software needed to       |
   |       |                   | install this software.                |
   +-------+-------------------+---------------------------------------+
   | 6     | parent            | The link references a software        |
   |       |                   | tag that is the parent of the         |
   |       |                   | referencing tag.  This                |
   |       |                   | relationship can be used when         |
   |       |                   | multiple software components are      |
   |       |                   | part of a software bundle, where      |
   |       |                   | the "parent" is the software tag      |
   |       |                   | for the bundle, and each child is     |
   |       |                   | a "component".  In such a case,       |
   |       |                   | each child component can provide      |
   |       |                   | a "parent" link relationship to       |
   |       |                   | the bundle's software tag, and        |
   |       |                   | the bundle can provide a              |
   |       |                   | "component" link relationship to      |
   |       |                   | each child software component.        |
   +-------+-------------------+---------------------------------------+
   | 7     | patches           | The link references a software        |
   |       |                   | tag that the referencing software     |
   |       |                   | patches.  Typically only used for     |
   |       |                   | patch tags (see Section 1.1).         |
   +-------+-------------------+---------------------------------------+
   | 8     | requires          | The link references a                 |



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   |       |                   | prerequisite for installing this      |
   |       |                   | software.  A patch tag (see           |
   |       |                   | Section 1.1) can use this to          |
   |       |                   | represent base software or            |
   |       |                   | another patch that needs to be        |
   |       |                   | installed first.                      |
   +-------+-------------------+---------------------------------------+
   | 9     | see-also          | The link references other             |
   |       |                   | software that may be of interest      |
   |       |                   | that relates to this software.        |
   +-------+-------------------+---------------------------------------+
   | 10    | supersedes        | The link references another           |
   |       |                   | software that this software           |
   |       |                   | replaces.  A patch tag (see           |
   |       |                   | Section 1.1) can use this to          |
   |       |                   | represent another patch that this     |
   |       |                   | patch incorporates or replaces.       |
   +-------+-------------------+---------------------------------------+
   | 11    | supplemental      | The link references a software        |
   |       |                   | tag that the referencing tag          |
   |       |                   | supplements.  Used on                 |
   |       |                   | supplemental tags (see                |
   |       |                   | Section 1.1).                         |
   +-------+-------------------+---------------------------------------+

                     Table 6: Link Relationship Values

   The values above are registered in the IANA "Software ID Link
   Relationship Values" registry defined in Section 6.2.7.  Additional
   values will likely be registered over time.

4.5.  Link Use Values

   The following table indicates the index value to use for the link-
   entry group's use item (see Section 2.7).  These values match the
   link use values defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  The "Index" value indicates the value to use as the
   link-entry group use item's value.  The "Use Type" provides human-
   readable text for the value.  The "Definition" describes the semantic
   meaning of each entry.











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     +=======+=============+========================================+
     | Index | Use Type    | Definition                             |
     +=======+=============+========================================+
     | 1     | optional    | From [SWID], "Not absolutely required; |
     |       |             | the [Link]'d software is installed     |
     |       |             | only when specified."                  |
     +-------+-------------+----------------------------------------+
     | 2     | required    | From [SWID], "The [Link]'d software is |
     |       |             | absolutely required for an operation   |
     |       |             | software installation."                |
     +-------+-------------+----------------------------------------+
     | 3     | recommended | From [SWID], "Not absolutely required; |
     |       |             | the [Link]'d software is installed     |
     |       |             | unless specified otherwise."           |
     +-------+-------------+----------------------------------------+

                         Table 7: Link Use Values

   The values above are registered in the IANA "Software ID Link Use
   Values" registry defined in Section 6.2.8.  Additional values will
   likely be registered over time.

5.  URI Schemes

   This specification defines the following URI schemes for use in
   CoSWID and to provide interoperability with schemes used in [SWID].

   Note: These URI schemes are used in [SWID] without an IANA
   registration.  The present specification ensures that these URI
   schemes are properly defined going forward.


   // RFC Ed.: throughout this section, please replace RFC-AAAA with the
   // RFC number of this specification and remove this note.

5.1.  "swid" URI Scheme

   There is a need for a scheme name that can be used in URIs that point
   to a specific software tag by that tag's tag-id, such as the use of
   the link entry as described in Section 2.7.  Since this scheme is
   used both in a standards track document and an ISO standard, this
   scheme needs to be used without fear of conflicts with current or
   future actual schemes.  In Section 6.6.1, the scheme "swid" is
   registered as a 'permanent' scheme for that purpose.

   URIs specifying the "swid" scheme are used to reference a software
   tag by its tag-id.  A tag-id referenced in this way can be used to
   identify the tag resource in the context of where it is referenced



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   from.  For example, when a tag is installed on a given device, that
   tag can reference related tags on the same device using URIs with
   this scheme.

   For URIs that use the "swid" scheme, the scheme specific part MUST
   consist of a referenced software tag's tag-id.  This tag-id MUST be
   URI encoded according to Section 2.1 of [RFC3986].

   The following expression is a valid example:

   swid:2df9de35-0aff-4a86-ace6-f7dddd1ade4c

5.2.  "swidpath" URI Scheme

   There is a need for a scheme name that can be used in URIs to
   identify a collection of specific software tags with data elements
   that match an XPath expression, such as the use of the link entry as
   described in Section 2.7.  The scheme named "swidpath" is used for
   this purpose in [SWID], but not registered.  To enable usage without
   fear of conflicts with current or future actual schemes, the present
   document registers it as a 'permanent' scheme for that purpose (see
   Section 6.6.2).

   URIs specifying the "swidpath" scheme are used to filter tags out of
   a base collection, so that matching tags are included in the
   identified tag collection.  The XPath expression
   [W3C.REC-xpath20-20101214] references the data that must be found in
   a given software tag out of base collection for that tag to be
   considered a matching tag.  Tags to be evaluated (the base
   collection) include all tags in the context of where the "swidpath
   URI" is referenced from.  For example, when a tag is installed on a
   given device, that tag can reference related tags on the same device
   using a URI with this scheme.

   For URIs that use the "swidpath" scheme, the following requirements
   apply:

   *  The scheme specific part MUST be an XPath expression as defined by
      [W3C.REC-xpath20-20101214].  The included XPath expression will be
      URI encoded according to Section 2.1 of [RFC3986].

   *  This XPath is evaluated over SWID tags, or COSWID tags transformed
      into SWID tags, found on a system.  A given tag MUST be considered
      a match if the XPath evaluation result value has an effective
      boolean value of "true" according to [W3C.REC-xpath20-20101214],
      Section 2.4.3.





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6.  IANA Considerations

   This document has a number of IANA considerations, as described in
   the following subsections.  In summary, 6 new registries are
   established with this request, with initial entries provided for each
   registry.  New values for 5 other registries are also requested.

6.1.  CoSWID Items Registry

   This registry uses integer values as index values in CBOR maps.

   This document defines a new registry titled "CoSWID Items".  Future
   registrations for this registry are to be made based on [BCP26] as
   follows:

        +==================+=====================================+
        | Range            | Registration Procedures             |
        +==================+=====================================+
        | 0-32767          | Standards Action with Expert Review |
        +------------------+-------------------------------------+
        | 32768-4294967295 | Specification Required              |
        +------------------+-------------------------------------+

              Table 8: CoSWID Items Registration Procedures

   All negative values are reserved for Private Use.

   Initial registrations for the "CoSWID Items" registry are provided
   below.  Assignments consist of an integer index value, the item name,
   and a reference to the defining specification.

       +===============+===========================+===============+
       | Index         | Item Name                 | Specification |
       +===============+===========================+===============+
       | 0             | tag-id                    | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 1             | software-name             | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 2             | entity                    | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 3             | evidence                  | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 4             | link                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 5             | software-meta             | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 6             | payload                   | RFC-AAAA      |
       +---------------+---------------------------+---------------+



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       | 7             | hash                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 8             | corpus                    | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 9             | patch                     | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 10            | media                     | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 11            | supplemental              | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 12            | tag-version               | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 13            | software-version          | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 14            | version-scheme            | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 15            | lang                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 16            | directory                 | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 17            | file                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 18            | process                   | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 19            | resource                  | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 20            | size                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 21            | file-version              | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 22            | key                       | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 23            | location                  | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 24            | fs-name                   | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 25            | root                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 26            | path-elements             | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 27            | process-name              | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 28            | pid                       | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 29            | type                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 30            | Unassigned                |               |
       +---------------+---------------------------+---------------+



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       | 31            | entity-name               | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 32            | reg-id                    | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 33            | role                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 34            | thumbprint                | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 35            | date                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 36            | device-id                 | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 37            | artifact                  | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 38            | href                      | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 39            | ownership                 | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 40            | rel                       | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 41            | media-type                | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 42            | use                       | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 43            | activation-status         | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 44            | channel-type              | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 45            | colloquial-version        | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 46            | description               | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 47            | edition                   | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 48            | entitlement-data-required | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 49            | entitlement-key           | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 50            | generator                 | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 51            | persistent-id             | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 52            | product                   | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 53            | product-family            | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 54            | revision                  | RFC-AAAA      |
       +---------------+---------------------------+---------------+



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       | 55            | summary                   | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 56            | unspsc-code               | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 57            | unspsc-version            | RFC-AAAA      |
       +---------------+---------------------------+---------------+
       | 58-4294967295 | Unassigned                |               |
       +---------------+---------------------------+---------------+

                Table 9: CoSWID Items Initial Registrations

6.2.  Software ID Values Registries

   The following IANA registries provide a mechanism for new values to
   be added over time to common enumerations used by SWID and CoSWID.
   While neither the CoSWID nor SWID specification is subordinate to the
   other and will evolve as their respective standards group chooses,
   there is value in supporting alignment between the two standards.
   Shared use of common code points, as spelled out in these registries,
   will facilitate this alignment, hence the intent for shared use of
   these registries and the decision to use "swidsoftware-id" (rather
   than "swid" or "coswid") in registry names.

6.2.1.  Registration Procedures

   The following registries allow for the registration of index values
   and names.  New registrations will be permitted through either a
   Standards Action with Expert Review policy or a Specification
   Required policy [BCP26].

   The following registries also reserve the integer-based index values
   in the range of -1 to -256 for private use as defined by Section 4.1
   of [BCP26].  This allows values -1 to -24 to be expressed as a single
   uint_8t in CBOR, and values -25 to -256 to be expressed using an
   additional uint_8t in CBOR.

6.2.2.  Private Use of Index and Name Values

   The integer-based index values in the private use range (-1 to -256)
   are intended for testing purposes and closed environments; values in
   other ranges SHOULD NOT be assigned for testing.

   For names that correspond to private use index values, an
   Internationalized Domain Name prefix MUST be used to prevent name
   conflicts using the form:

   domainprefix/name




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   Where both "domainprefix" and "name" MUST each be either an NR-LDH
   label or a U-label as defined by [RFC5890], and "name" also MUST be a
   unique name within the namespace defined by the "domainprefix".  Use
   of a prefix in this way allows for a name to be used in the private
   use range.  This is consistent with the guidance in [BCP178].

6.2.3.  Expert Review Criteria

   Designated experts MUST ensure that new registration requests meet
   the following additional criteria:

   *  The requesting specification MUST provide a clear semantic
      definition for the new entry.  This definition MUST clearly
      differentiate the requested entry from other previously registered
      entries.

   *  The requesting specification MUST describe the intended use of the
      entry, including any co-constraints that exist between the use of
      the entry's index value or name, and other values defined within
      the SWID/CoSWID model.

   *  Index values and names outside the private use space MUST NOT be
      used without registration.  This is considered squatting and MUST
      be avoided.  Designated experts MUST ensure that reviewed
      specifications register all appropriate index values and names.

   *  Standards track documents MAY include entries registered in the
      range reserved for entries under the Specification Required
      policy.  This can occur when a standards track document provides
      further guidance on the use of index values and names that are in
      common use, but were not registered with IANA.  This situation
      SHOULD be avoided.

   *  All registered names MUST be valid according to the XML Schema
      NMTOKEN data type (see [W3C.REC-xmlschema-2-20041028],
      Section 3.3.4).  This ensures that registered names are compatible
      with the SWID format [SWID] where they are used.

   *  Registration of vanity names SHOULD be discouraged.  The
      requesting specification MUST provide a description of how a
      requested name will allow for use by multiple stakeholders.

6.2.4.  Software ID Version Scheme Values Registry

   This document establishes a new registry titled "Software ID Version
   Scheme Values".  This registry provides index values for use as
   version-scheme item values in this document and version scheme names
   for use in [SWID].



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   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/software-id]

   This registry uses the registration procedures defined in
   Section 6.2.1 with the following associated ranges:

           +=============+=====================================+
           | Range       | Registration Procedures             |
           +=============+=====================================+
           | 0-16383     | Standards Action with Expert Review |
           +-------------+-------------------------------------+
           | 16384-65535 | Specification Required              |
           +-------------+-------------------------------------+

             Table 10: Software ID Version Scheme Registration
                                 Procedures

   Assignments MUST consist of an integer Index value, the Version
   Scheme Name, and a reference to the defining specification.

   Initial registrations for the "Software ID Version Scheme Values"
   registry are provided below, which are derived from the textual
   version scheme names defined in [SWID].

        +=============+=========================+=================+
        | Index       | Version Scheme Name     | Specification   |
        +=============+=========================+=================+
        | 0           | Reserved                |                 |
        +-------------+-------------------------+-----------------+
        | 1           | multipartnumeric        | See Section 4.1 |
        +-------------+-------------------------+-----------------+
        | 2           | multipartnumeric+suffix | See Section 4.1 |
        +-------------+-------------------------+-----------------+
        | 3           | alphanumeric            | See Section 4.1 |
        +-------------+-------------------------+-----------------+
        | 4           | decimal                 | See Section 4.1 |
        +-------------+-------------------------+-----------------+
        | 5-16383     | Unassigned              |                 |
        +-------------+-------------------------+-----------------+
        | 16384       | semver                  | See Section 4.1 |
        +-------------+-------------------------+-----------------+
        | 16385-65535 | Unassigned              |                 |
        +-------------+-------------------------+-----------------+

         Table 11: Software ID Version Scheme Initial Registrations

   Registrations MUST conform to the expert review criteria defined in
   Section 6.2.3.



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   Designated experts MUST also ensure that newly requested entries
   define a value space for the corresponding version item that is
   unique from other previously registered entries.  Note: The initial
   registrations violate this requirement, but are included for
   backwards compatibility with [SWID].  See also Section 4.1.

6.2.5.  Software ID Entity Role Values Registry

   This document establishes a new registry titled "Software ID Entity
   Role Values".  This registry provides index values for use as entity-
   entry role item values in this document and entity role names for use
   in [SWID].

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/software-id]

   This registry uses the registration procedures defined in
   Section 6.2.1 with the following associated ranges:

             +=========+=====================================+
             | Range   | Registration Procedures             |
             +=========+=====================================+
             | 0-127   | Standards Action with Expert Review |
             +---------+-------------------------------------+
             | 128-255 | Specification Required              |
             +---------+-------------------------------------+

                     Table 12: Software ID Entity Role
                          Registration Procedures

   Assignments consist of an integer Index value, a Role Name, and a
   reference to the defining specification.

   Initial registrations for the "Software ID Entity Role Values"
   registry are provided below, which are derived from the textual
   entity role names defined in [SWID].















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               +=======+=================+=================+
               | Index | Role Name       | Specification   |
               +=======+=================+=================+
               | 0     | Reserved        |                 |
               +-------+-----------------+-----------------+
               | 1     | tagCreator      | See Section 4.2 |
               +-------+-----------------+-----------------+
               | 2     | softwareCreator | See Section 4.2 |
               +-------+-----------------+-----------------+
               | 3     | aggregator      | See Section 4.2 |
               +-------+-----------------+-----------------+
               | 4     | distributor     | See Section 4.2 |
               +-------+-----------------+-----------------+
               | 5     | licensor        | See Section 4.2 |
               +-------+-----------------+-----------------+
               | 6     | maintainer      | See Section 4.2 |
               +-------+-----------------+-----------------+
               | 7-255 | Unassigned      |                 |
               +-------+-----------------+-----------------+

                 Table 13: Software ID Entity Role Initial
                               Registrations

   Registrations MUST conform to the expert review criteria defined in
   Section 6.2.3.

6.2.6.  Software ID Link Ownership Values Registry

   This document establishes a new registry titled "Software ID Link
   Ownership Values".  This registry provides index values for use as
   link-entry ownership item values in this document and link ownership
   names for use in [SWID].

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/software-id]

   This registry uses the registration procedures defined in
   Section 6.2.1 with the following associated ranges:













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             +=========+=====================================+
             | Range   | Registration Procedures             |
             +=========+=====================================+
             | 0-127   | Standards Action with Expert Review |
             +---------+-------------------------------------+
             | 128-255 | Specification Required              |
             +---------+-------------------------------------+

                    Table 14: Software ID Link Ownership
                          Registration Procedures

   Assignments consist of an integer Index value, an Ownership Type
   Name, and a reference to the defining specification.

   Initial registrations for the "Software ID Link Ownership Values"
   registry are provided below, which are derived from the textual
   entity role names defined in [SWID].

             +=======+=====================+=================+
             | Index | Ownership Type Name | Definition      |
             +=======+=====================+=================+
             | 0     | Reserved            |                 |
             +-------+---------------------+-----------------+
             | 1     | abandon             | See Section 4.3 |
             +-------+---------------------+-----------------+
             | 2     | private             | See Section 4.3 |
             +-------+---------------------+-----------------+
             | 3     | shared              | See Section 4.3 |
             +-------+---------------------+-----------------+
             | 4-255 | Unassigned          |                 |
             +-------+---------------------+-----------------+

                Table 15: Software ID Link Ownership Inital
                               Registrations

   Registrations MUST conform to the expert review criteria defined in
   Section 6.2.3.

6.2.7.  Software ID Link Relationship Values Registry

   This document establishes a new registry titled "Software ID Link
   Relationship Values".  This registry provides index values for use as
   link-entry rel item values in this document and link ownership names
   for use in [SWID].

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/software-id]




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   This registry uses the registration procedures defined in
   Section 6.2.1 with the following associated ranges:

           +=============+=====================================+
           | Range       | Registration Procedures             |
           +=============+=====================================+
           | 0-32767     | Standards Action with Expert Review |
           +-------------+-------------------------------------+
           | 32768-65535 | Specification Required              |
           +-------------+-------------------------------------+

                  Table 16: Software ID Link Relationship
                          Registration Procedures

   Assignments consist of an integer Index value, the Relationship Type
   Name, and a reference to the defining specification.

   Initial registrations for the "Software ID Link Relationship Values"
   registry are provided below, which are derived from the link
   relationship values defined in [SWID].































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          +==========+========================+=================+
          | Index    | Relationship Type Name | Specification   |
          +==========+========================+=================+
          | 0        | Reserved               |                 |
          +----------+------------------------+-----------------+
          | 1        | ancestor               | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 2        | component              | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 3        | feature                | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 4        | installationmedia      | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 5        | packageinstaller       | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 6        | parent                 | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 7        | patches                | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 8        | requires               | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 9        | see-also               | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 10       | supersedes             | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 11       | supplemental           | See Section 4.4 |
          +----------+------------------------+-----------------+
          | 12-65535 | Unassigned             |                 |
          +----------+------------------------+-----------------+

              Table 17: Software ID Link Relationship Initial
                               Registrations

   Registrations MUST conform to the expert review criteria defined in
   Section 6.2.3.

   Designated experts MUST also ensure that a newly requested entry
   documents the URI schemes allowed to be used in an href associated
   with the link relationship and the expected resolution behavior of
   these URI schemes.  This will help to ensure that applications
   processing software tags are able to interoperate when resolving
   resources referenced by a link of a given type.









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6.2.8.  Software ID Link Use Values Registry

   This document establishes a new registry titled "Software ID Link Use
   Values".  This registry provides index values for use as link-entry
   use item values in this document and link use names for use in
   [SWID].

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/software-id]

   This registry uses the registration procedures defined in
   Section 6.2.1 with the following associated ranges:

             +=========+=====================================+
             | Range   | Registration Procedures             |
             +=========+=====================================+
             | 0-127   | Standards Action with Expert Review |
             +---------+-------------------------------------+
             | 128-255 | Specification Required              |
             +---------+-------------------------------------+

                Table 18: Software ID Link Use Registration
                                 Procedures

   Assignments consist of an integer Index value, the Link Use Type
   Name, and a reference to the defining specification.

   Initial registrations for the "Software ID Link Use Values" registry
   are provided below, which are derived from the link relationship
   values defined in [SWID].

             +=======+====================+=================+
             | Index | Link Use Type Name | Specification   |
             +=======+====================+=================+
             | 0     | Reserved           |                 |
             +-------+--------------------+-----------------+
             | 1     | optional           | See Section 4.5 |
             +-------+--------------------+-----------------+
             | 2     | required           | See Section 4.5 |
             +-------+--------------------+-----------------+
             | 3     | recommended        | See Section 4.5 |
             +-------+--------------------+-----------------+
             | 4-255 | Unassigned         |                 |
             +-------+--------------------+-----------------+

                  Table 19: Software ID Link Use Initial
                              Registrations




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   Registrations MUST conform to the expert review criteria defined in
   Section 6.2.3.

6.3.  swid+cbor Media Type Registration

   IANA is requested to add the following to the IANA "Media Types"
   registry [IANA.media-types].

   Type name: application

   Subtype name: swid+cbor

   Required parameters: none

   Optional parameters: none

   Encoding considerations: Binary (encoded as CBOR [RFC8949]).  See
   RFC-AAAA for details.

   Security considerations: See Section 9 of RFC-AAAA.

   Interoperability considerations: Applications MAY ignore any key
   value pairs that they do not understand.  This allows backwards
   compatible extensions to this specification.

   Published specification: RFC-AAAA

   Applications that use this media type: The type is used by software
   asset management systems, vulnerability assessment systems, and in
   applications that use remote integrity verification.

   Fragment Identifier Considerations: The syntax and semantics of
   fragment identifiers specified for "application/swid+cbor" are as
   specified for "application/cbor".  (At publication of RFC-AAAA, there
   is no fragment identification syntax defined for "application/cbor".)

   Additional information:

   Magic number(s): if tagged, first five bytes in hex: da 53 57 49 44
   (see Section 8 in RFC-AAAA)

   File extension(s): coswid

   Macintosh file type code(s): none

   Macintosh Universal Type Identifier code: org.ietf.coswid conforms to
   public.data




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   Person & email address to contact for further information: IESG
   <iesg@ietf.org>

   Intended usage: COMMON

   Restrictions on usage: None

   Author: Henk Birkholz <henk.birkholz@sit.fraunhofer.de>

   Change controller: IESG

6.4.  CoAP Content-Format Registration

   IANA is requested to assign a CoAP Content-Format ID for the CoSWID
   media type in the "CoAP Content-Formats" sub-registry, from the "IETF
   Review or IESG Approval" space (256..999), within the "CoRE
   Parameters" registry [RFC7252] [IANA.core-parameters]:

          +=======================+==========+======+===========+
          | Media type            | Encoding | ID   | Reference |
          +=======================+==========+======+===========+
          | application/swid+cbor | -        | TBD1 | RFC-AAAA  |
          +-----------------------+----------+------+-----------+

                     Table 20: CoAP Content-Format IDs

6.5.  CBOR Tag Registration

   IANA is requested to allocate a tag in the "CBOR Tags" registry
   [IANA.cbor-tags], preferably with the specific value requested:

         +============+===========+=============================+
         | Tag        | Data Item | Semantics                   |
         +============+===========+=============================+
         | 1398229316 | map       | Concise Software Identifier |
         |            |           | (CoSWID) [RFC-AAAA]         |
         +------------+-----------+-----------------------------+

                        Table 21: CoSWID CBOR Tag

6.6.  URI Scheme Registrations

   The ISO 19770-2:2015 SWID specification describes use of the "swid"
   and "swidpath" URI schemes, which are currently in use in
   implementations.  This document continues this use for CoSWID.  The
   following subsections provide registrations for these schemes in to
   ensure that a permanent registration exists for these schemes that is
   suitable for use in the SWID and CoSWID specifications.



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   URI schemes are registered within the "Uniform Resource Identifier
   (URI) Schemes" registry maintained at [IANA.uri-schemes].

6.6.1.  URI-scheme swid

   IANA is requested to register the URI scheme "swid".  This
   registration request complies with [RFC7595].

   Scheme name:
      swid

   Status:
      Permanent

   Applications/protocols that use this scheme name:
      Applications that require Software-IDs (SWIDs) or Concise
      Software-IDs (CoSWIDs); see Section 5.1 of RFC-AAAA.

   Contact:
      IETF Chair <chair@ietf.org>

   Change controller:
      IESG <iesg@ietf.org>

   Reference:
      Section 5.1 in RFC-AAAA

6.6.2.  URI-scheme swidpath

   IANA is requested to register the URI scheme "swidpath".  This
   registration request complies with [RFC7595].

   Scheme name:
      swidpath

   Status:
      Permanent

   Applications/protocols that use this scheme name:
      Applications that require Software-IDs (SWIDs) or Concise
      Software-IDs (CoSWIDs); see Section 5.2 of RFC-AAAA.

   Contact:
      IETF Chair <chair@ietf.org>

   Change controller:
      IESG <iesg@ietf.org>




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   Reference:
      Section 5.2 in RFC-AAAA

6.7.  CoSWID Model for use in SWIMA Registration

   The Software Inventory Message and Attributes (SWIMA) for PA-TNC
   specification [RFC8412] defines a standardized method for collecting
   an endpoint device's software inventory.  A CoSWID can provide
   evidence of software installation which can then be used and
   exchanged with SWIMA.  This registration adds a new entry to the IANA
   "Software Data Model Types" registry defined by [RFC8412]
   [IANA.pa-tnc-parameters] to support CoSWID use in SWIMA as follows:

   Pen: 0

   Integer: TBD2

   Name: Concise Software Identifier (CoSWID)

   Reference: RFC-AAAA

   Deriving Software Identifiers:

   A Software Identifier generated from a CoSWID tag is expressed as a
   concatenation of the form in [RFC5234] as follows:

   TAG_CREATOR_REGID "_" "_" UNIQUE_ID

   Where TAG_CREATOR_REGID is the reg-id item value of the tag's entity
   item having the role value of 1 (corresponding to "tag creator"), and
   the UNIQUE_ID is the same tag's tag-id item.  If the tag-id item's
   value is expressed as a 16-byte binary string, the UNIQUE_ID MUST be
   represented using the UUID string representation defined in [RFC4122]
   including the "urn:uuid:" prefix.

   The TAG_CREATOR_REGID and the UNIQUE_ID are connected with a double
   underscore (_), without any other connecting character or whitespace.

7.  Signed CoSWID Tags

   SWID tags, as defined in the ISO-19770-2:2015 XML schema, can include
   cryptographic signatures to protect the integrity of the SWID tag.
   In general, tags are signed by the tag creator (typically, although
   not exclusively, the vendor of the software component that the SWID
   tag identifies).  Cryptographic signatures can make any modification
   of the tag detectable, which is especially important if the integrity
   of the tag is important, such as when the tag is providing reference
   integrity measurements for files.  The ISO-19770-2:2015 XML schema



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   uses XML DSIG to support cryptographic signatures.

   Signing CoSWID tags follows the procedures defined in CBOR Object
   Signing and Encryption [I-D.ietf-cose-rfc8152bis-struct].  A CoSWID
   tag MUST be wrapped in a COSE Signature structure, either COSE_Sign1
   or COSE_Sign.  In the first case, a Single Signer Data Object
   (COSE_Sign1) contains a single signature and MUST be signed by the
   tag creator.  The following CDDL specification defines a restrictive
   subset of COSE header parameters that MUST be used in the protected
   header in this case.

   <CODE BEGINS>
   COSE-Sign1-coswid<payload> = [
       protected: bstr .cbor protected-signed-coswid-header,
       unprotected: unprotected-signed-coswid-header,
       payload: bstr .cbor payload,
       signature: bstr,
   ]

   cose-label = int / tstr
   cose-values = any

   protected-signed-coswid-header = {
       1 => int,                      ; algorithm identifier
       3 => "application/swid+cbor",
       * cose-label => cose-values,
   }

   unprotected-signed-coswid-header = {
       * cose-label => cose-values,
   }
   <CODE ENDS>

   The COSE_Sign structure allows for more than one signature, one of
   which MUST be issued by the tag creator, to be applied to a CoSWID
   tag and MAY be used.  The corresponding usage scenarios are domain-
   specific and require well-specified application guidance.














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   <CODE BEGINS>
   COSE-Sign-coswid<payload> = [
       protected: bstr .cbor protected-signed-coswid-header1,
       unprotected: unprotected-signed-coswid-header,
       payload: bstr .cbor payload,
       signature: [ * COSE_Signature ],
   ]

   protected-signed-coswid-header1 = {
       3 => "application/swid+cbor",
       * cose-label => cose-values,
   }

   protected-signature-coswid-header = {
       1 => int,                      ; algorithm identifier
       * cose-label => cose-values,
   }

   unprotected-sign-coswid-header = {
       * cose-label => cose-values,
   }

   COSE_Signature =  [
       protected: bstr .cbor protected-signature-coswid-header,
       unprotected: unprotected-sign-coswid-header,
       signature : bstr
   ]
   <CODE ENDS>

   Additionally, the COSE Header counter signature MAY be used as an
   attribute in the unprotected header map of the COSE envelope of a
   CoSWID [I-D.ietf-cose-countersign].  The application of counter
   signing enables second parties to provide a signature on a signature
   allowing for a proof that a signature existed at a given time (i.e.,
   a timestamp).

   A CoSWID MUST be signed, using the above mechanism, to protect the
   integrity of the CoSWID tag.  See the security considerations (in
   Section 9) for more information on why a signed CoSWID is valuable in
   most cases.











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8.  CBOR-Tagged CoSWID Tags

   This specification allows for tagged and untagged CBOR data items
   that are CoSWID tags.  Consecutively, the CBOR tag for CoSWID tags
   defined in Table 21 SHOULD be used in conjunction with CBOR data
   items that are a CoSWID tags.  Other CBOR tags MUST NOT be used with
   a CBOR data item that is a CoSWID tag.  If tagged, both signed and
   unsigned CoSWID tags MUST use the CoSWID CBOR tag.  In case a signed
   CoSWID is tagged, a CoSWID CBOR tag MUST be appended before the COSE
   envelope whether it is a COSE_Untagged_Message or a
   COSE_Tagged_Message.  In case an unsigned CoSWID is tagged, a CoSWID
   CBOR tag MUST be appended before the CBOR data item that is the
   CoSWID tag.

   <CODE BEGINS>
   coswid = unsigned-coswid / signed-coswid
   unsigned-coswid = concise-swid-tag / tagged-coswid<concise-swid-tag>
   signed-coswid1 = signed-coswid-for<unsigned-coswid>
   signed-coswid = signed-coswid1 / tagged-coswid<signed-coswid1>

   tagged-coswid<T> = #6.1398229316(T)

   signed-coswid-for<payload> = #6.18(COSE-Sign1-coswid<payload>)
       / #6.98(COSE-Sign-coswid<payload>)
   <CODE ENDS>

   This specification allows for a tagged CoSWID tag to reside in a COSE
   envelope that is also tagged with a CoSWID CBOR tag.  In cases where
   a tag creator is not a signer (e.g., hand-offs between entities in a
   trusted portion of a supply-chain), retaining CBOR tags attached to
   unsigned CoSWID tags can be of great use.  Nevertheless, redundant
   use of tags SHOULD be avoided when possible.

9.  Security Considerations

   The following security considerations for use of CoSWID tags focus
   on:

   *  ensuring the integrity and authenticity of a CoSWID tag

   *  the application of CoSWID tags to address security challenges
      related to unmanaged or unpatched software

   *  reducing the potential for unintended disclosure of a device's
      software load






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   A tag is considered "authoritative" if the CoSWID tag was created by
   the software provider.  An authoritative CoSWID tag contains
   information about a software component provided by the supplier of
   the software component, who is expected to be an expert in their own
   software.  Thus, authoritative CoSWID tags can represent
   authoritative information about the software component.  The degree
   to which this information can be trusted depends on the tag's chain
   of custody and the ability to verify a signature provided by the
   supplier if present in the CoSWID tag.  The provisioning and
   validation of CoSWID tags are handled by local policy and is outside
   the scope of this document.

   A signed CoSWID tag (see Section 7) whose signature has been
   validated can be relied upon to be unchanged since it was signed.  By
   contrast, the data contained in unsigned tags can be altered by any
   user or process with write-access to the tag.  To support signature
   validation, there is the need to associate the right key with the
   software provider or party originating the signature in a secure way.
   This operation is application specific and needs to be addressed by
   the application or a user of the application; a specific approach for
   which is out-of-scope for this document.

   When an authoritative tag is signed, the originator of the signature
   can be verified.  A trustworthy association between the signature and
   the originator of the signature can be established via trust anchors.
   A certification path between a trust anchor and a certificate
   including a public key enabling the validation of a tag signature can
   realize the assessment of trustworthiness of an authoritative tag.
   Verifying that the software provider is the signer is a different
   matter.  This requires an association between the signature and the
   tag's entity item associated corresponding to the software provider.
   No mechanism is defined in this draft to make this association;
   therefore, this association will need to be handled by local policy.
   As always, the validity of a signature does not imply veracity of the
   signed statements: anyone can sign assertions such that the software
   is from a specific software-creator or that a specific persistent-id
   applies; policy needs to be applied to evaluate these statements and
   to determine their suitability for a specific use.

   Loss of control of signing credentials used to sign CoSWID tags would
   create doubt about the authenticity and integrity of any CoSWID tags
   signed using the compromised keys.  In such cases, the legitimate tag
   signer (namely, the software provider for an authoritative CoSWID
   tag) can employ uncompromised signing credentials to create a new
   signature on the original tag.  The tag version number would not be
   incremented since the tag itself was not modified.  Consumers of
   CoSWID tags would need to validate the tag using the new credentials
   and would also need to make use of revocation information available



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   for the compromised credentials to avoid validating tags signed with
   them.  The process for doing this is beyond the scope of this
   specification.

   The CoSWID format allows the use of hash values without an
   accompanying hash algorithm identifier.  This exposes the tags to
   some risk of cross-algorithm attacks.  We believe that this can
   become a practical problem only if some implementations allow the use
   of insecure hash algorithms.  Since it may not become known
   immediately when an algorithm becomes insecure, this leads to a
   strong recommendation to only include support for hash algorithms
   that are generally considered secure, and not just marginally so.

   CoSWID tags are intended to contain public information about software
   components and, as such, the contents of a CoSWID tag (as opposed to
   the set of tags that apply to the endpoint, see below) does not need
   to be protected against unintended disclosure on an endpoint.
   Conversely, generators of CoSWID tags need to ensure that only public
   information is disclosed.  Entitlement Keys are an example for
   information where particular care is required; tag authors are
   advised not to record unprotected, private software license keys in
   this field.

   CoSWID tags are intended to be easily discoverable by authorized
   applications and users on an endpoint in order to make it easy to
   determine the tagged software load.  Access to the collection of an
   endpoint's CoSWID tags needs to be appropriately controlled to
   authorized applications and users using an appropriate access control
   mechanism.

   Since the tag-id of a CoSWID tag can be used as a global index value,
   failure to ensure the tag-id's uniqueness can cause collisions or
   ambiguity in CoSWID tags that are retrieved or processed using this
   identifier.  CoSWID is designed to not require a registry of
   identifiers.  As a result, CoSWID requires the tag creator to employ
   a method of generating a unique tag identifier.  Specific methods of
   generating a unique identifier are beyond the scope of this
   specification.  A collision in tag-ids may result in false positives/
   negatives in software integrity checks or mis-identification of
   installed software, undermining CoSWID use cases such as
   vulnerability identification, software inventory, etc.  If such a
   collision is detected, then the tag consumer may want to contact the
   maintainer of the CoSWID to have them issue a correction addressing
   the collision; however, this also discloses to the maintainer that
   the consumer has the other tag with the given tag-id in their
   database.  More generally speaking, a tag consumer needs to be robust
   against such collisions lest the collision become a viable attack
   vector.



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   CoSWID tags are designed to be easily added and removed from an
   endpoint along with the installation or removal of software
   components.  On endpoints where addition or removal of software
   components is tightly controlled, the addition or removal of CoSWID
   tags can be similarly controlled.  On more open systems, where many
   users can manage the software inventory, CoSWID tags can be easier to
   add or remove.  On such systems, it can be possible to add or remove
   CoSWID tags in a way that does not reflect the actual presence or
   absence of corresponding software components.  Similarly, not all
   software products automatically install CoSWID tags, so products can
   be present on an endpoint without providing a corresponding CoSWID
   tag.  As such, any collection of CoSWID tags cannot automatically be
   assumed to represent either a complete or fully accurate
   representation of the software inventory of the endpoint.  However,
   especially on endpoint devices that more strictly control the ability
   to add or remove applications, CoSWID tags are an easy way to provide
   a preliminary understanding of that endpoint's software inventory.

   As CoSWID tags do not expire, inhibiting new CoSWID tags from
   reaching an intended consumer would render that consumer stuck with
   outdated information, potentially leaving associated vulnerabilities
   or weaknesses unmitigated.  Therefore, a CoSWID tag consumer should
   actively check for updated tag-versions via more than one means.

   This specification makes use of relative paths (e.g., filesystem
   paths) in several places.  A signed COSWID tag cannot make use of
   these to derive information that is considered to be covered under
   the signature.  Typically, relative file system paths will be used to
   identify targets for an installation, not sources of tag information.






















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   Any report of an endpoint's CoSWID tag collection provides
   information about the software inventory of that endpoint.  If such a
   report is exposed to an attacker, this can tell them which software
   products and versions thereof are present on the endpoint.  By
   examining this list, the attacker might learn of the presence of
   applications that are vulnerable to certain types of attacks.  As
   noted earlier, CoSWID tags are designed to be easily discoverable by
   authorized applications and users on an endpoint, but this does not
   present a significant risk since an attacker would already need to
   have access to the endpoint to view that information.  However, when
   the endpoint transmits its software inventory to another party, or
   that inventory is stored on a server for later analysis, this can
   potentially expose this information to attackers who do not yet have
   access to the endpoint.  For this reason, it is important to protect
   the confidentiality of CoSWID tag information that has been collected
   from an endpoint in transit and at rest, not because those tags
   individually contain sensitive information, but because the
   collection of CoSWID tags and their association with an endpoint
   reveals information about that endpoint's attack surface.

   Finally, both the ISO-19770-2:2015 XML schema SWID definition and the
   CoSWID CDDL specification allow for the construction of "infinite"
   tags with link item loops or tags that contain malicious content with
   the intent of creating non-deterministic states during validation or
   processing of those tags.  While software providers are unlikely to
   do this, CoSWID tags can be created by any party and the CoSWID tags
   collected from an endpoint could contain a mixture of vendor and non-
   vendor created tags.  For this reason, a CoSWID tag might contain
   potentially malicious content.  Input sanitization, loop detection,
   and signature verification are ways that implementations can address
   this concern.

   More generally speaking, the security considerations of [RFC8949],
   [I-D.ietf-cose-rfc8152bis-struct], and [I-D.ietf-cose-countersign]
   apply.

10.  Privacy Consideration

   As noted in Section 9, collected information about an endpoint's
   software load, such as what might be represented by an endpoint's
   CoSWID tag collection, could be used to identify vulnerable software
   for attack.  Collections of endpoint software information also can
   have privacy implications for users.  The set of application a user
   installs can give clues to personal matters such as political
   affiliation, banking and investments, gender, sexual orientation,
   medical concerns, etc.  While the collection of CoSWID tags on an
   endpoint wouldn't increase the privacy risk (since a party able to
   view those tags could also view the applications themselves), if



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   those CoSWID tags are gathered and stored in a repository somewhere,
   visibility into the repository now also gives visibility into a
   user's application collection.  For this reason, repositories of
   collected CoSWID tags not only need to be protected against
   collection by malicious parties, but even authorized parties will
   need to be vetted and made aware of privacy responsibilities
   associated with having access to this information.  Likewise, users
   should be made aware that their software inventories are being
   collected from endpoints.  Furthermore, when collected and stored by
   authorized parties or systems, the inventory data needs to be
   protected as both security and privacy-sensitive information.

11.  Change Log

   This section is to be removed before publishing as an RFC.

   [THIS SECTION TO BE REMOVED BY THE RFC EDITOR.]

   Changes from version 12 to version 14:

   *  Moved key identifier to protected COSE header

   *  Fixed index reference for hash

   *  Removed indirection of CDDL type definition for filesystem-item

   *  Fixed quantity of resource and process

   *  Updated resource-collection

   *  Renamed socket name in software-meta to be consistent in naming

   *  Aligned excerpt examples in I-D text with full CDDL

   *  Fixed titles where title was referring to group instead of map

   *  Added missing date in SEMVER

   *  Fixed root cardinality for file and directory, etc.

   *  Transformed path-elements-entry from map to group for re-usability

   *  Scrubbed IANA Section

   *  Removed redundant supplemental rule

   *  Aligned discrepancy with ISO spec.




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   *  Addressed comments on typos.

   *  Fixed kramdown nits and BCP reference.

   *  Addressed comments from WGLC reviewers.

   Changes in version 12:

   *  Addressed a bunch of minor editorial issues based on WGLC
      feedback.

   *  Added text about the use of UTF-8 in CoSWID.

   *  Adjusted tag-id to allow for a UUID to be provided as a bstr.

   *  Cleaned up descriptions of index ranges throughout the document,
      removing discussion of 8 bit, 16 bit, etc.

   *  Adjusted discussion of private use ranges to use negative integer
      values and to be more clear throughout the document.

   *  Added discussion around resolving overlapping value spaces for
      version schemes.

   *  Added a set of expert review criteria for new IANA registries
      created by this document.

   *  Added new registrations for the "swid" and "swidpath" URI schemes,
      and for using CoSWID with SWIMA.

   Changes from version 03 to version 11:

   *  Reduced representation complexity of the media-entry type and
      removed the Section describing the older data structure.

   *  Added more signature schemes from COSE

   *  Included a minimal required set of normative language

   *  Reordering of attribute name to integer label by priority
      according to semantics.

   *  Added an IANA registry for CoSWID items supporting future
      extension.

   *  Cleaned up IANA registrations, fixing some inconsistencies in the
      table labels.




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   *  Added additional CDDL sockets for resource collection entries
      providing for additional extension points to address future SWID/
      CoSWID extensions.

   *  Updated Section on extension points to address new CDDL sockets
      and to reference the new IANA registry for items.

   *  Removed unused references and added new references to address
      placeholder comments.

   *  Added table with semantics for the link ownership item.

   *  Clarified language, made term use more consistent, fixed
      references, and replacing lowercase RFC2119 keywords.

   Changes from version 02 to version 03:

   *  Updated core CDDL including the CDDL design pattern according to
      RFC 8428.

   Changes from version 01 to version 02:

   *  Enforced a more strict separation between the core CoSWID
      definition and additional usage by moving content to corresponding
      appendices.

   *  Removed artifacts inherited from the reference schema provided by
      ISO (e.g., NMTOKEN(S))

   *  Simplified the core data definition by removing group and type
      choices where possible

   *  Minor reordering of map members

   *  Added a first extension point to address requested flexibility for
      extensions beyond the any-element

   Changes from version 00 to version 01:

   *  Ambiguity between evidence and payload eliminated by introducing
      explicit members (while still

   *  allowing for "empty" SWID tags)

   *  Added a relatively restrictive COSE envelope using cose_sign1 to
      define signed CoSWID (single signer only, at the moment)





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   *  Added a definition how to encode hashes that can be stored in the
      any-member using existing IANA tables to reference hash-algorithms

   Changes since adopted as a WG I-D -00:

   *  Removed redundant any-attributes originating from the ISO-
      19770-2:2015 XML schema definition

   *  Fixed broken multi-map members

   *  Introduced a more restrictive item (any-element-map) to represent
      custom maps, increased restriction on types for the any-attribute,
      accordingly

   *  Fixed X.1520 reference

   *  Minor type changes of some attributes (e.g., NMTOKENS)

   *  Added semantic differentiation of various name types (e,g. fs-
      name)

   Changes from version 06 to version 07:

   *  Added type choices/enumerations based on textual definitions in
      19770-2:2015

   *  Added value registry request

   *  Added media type registration request

   *  Added content format registration request

   *  Added CBOR tag registration request

   *  Removed RIM appendix to be addressed in complementary draft

   *  Removed CWT appendix

   *  Flagged firmware resource collection appendix for revision

   *  Made use of terminology more consistent

   *  Better defined use of extension points in the CDDL

   *  Added definitions for indexed values

   *  Added IANA registry for Link use indexed values




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   Changes from version 05 to version 06:

   *  Improved quantities

   *  Included proposals for implicit enumerations that were NMTOKENS

   *  Added extension points

   *  Improved exemplary firmware-resource extension

   Changes from version 04 to version 05:

   *  Clarified language around SWID and CoSWID to make more consistent
      use of these terms.

   *  Added language describing CBOR optimizations for single vs. arrays
      in the model front matter.

   *  Fixed a number of grammatical, spelling, and wording issues.

   *  Documented extension points that use CDDL sockets.

   *  Converted IANA registration tables to markdown tables, reserving
      the 0 value for use when a value is not known.

   *  Updated a number of references to their current versions.

   Changes from version 03 to version 04:

   *  Re-index label values in the CDDL.

   *  Added a Section describing the CoSWID model in detail.

   *  Created IANA registries for entity-role and version-scheme

   Changes from version 02 to version 03:

   *  Updated CDDL to allow for a choice between a payload or evidence

   *  Re-index label values in the CDDL.

   *  Added item definitions

   *  Updated references for COSE, CBOR Web Token, and CDDL.

   Changes from version 01 to version 02:





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   *  Added extensions for Firmware and CoSWID use as Reference
      Integrity Measurements (CoSWID RIM)

   *  Changes meta handling in CDDL from use of an explicit use of items
      to a more flexible unconstrained collection of items.

   *  Added Sections discussing use of COSE Signatures and CBOR Web
      Tokens

   Changes from version 00 to version 01:

   *  Added CWT usage for absolute SWID paths on a device

   *  Fixed cardinality of type-choices including arrays

   *  Included first iteration of firmware resource-collection

12.  References

12.1.  Normative References

   [BCP178]   Saint-Andre, P., Crocker, D., and M. Nottingham,
              "Deprecating the "X-" Prefix and Similar Constructs in
              Application Protocols", BCP 178, RFC 6648,
              DOI 10.17487/RFC6648, June 2012,
              <https://www.rfc-editor.org/info/rfc6648>.

   [BCP26]    Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [I-D.ietf-cose-countersign]
              Schaad, J. and R. Housley, "CBOR Object Signing and
              Encryption (COSE): Countersignatures", Work in Progress,
              Internet-Draft, draft-ietf-cose-countersign-05, 23 June
              2021, <https://www.ietf.org/archive/id/draft-ietf-cose-
              countersign-05.txt>.

   [I-D.ietf-cose-rfc8152bis-struct]
              Schaad, J., "CBOR Object Signing and Encryption (COSE):
              Structures and Process", Work in Progress, Internet-Draft,
              draft-ietf-cose-rfc8152bis-struct-15, 1 February 2021,
              <https://www.ietf.org/archive/id/draft-ietf-cose-
              rfc8152bis-struct-15.txt>.






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   [IANA.cbor-tags]
              IANA, "Concise Binary Object Representation (CBOR) Tags",
              19 September 2013,
              <https://www.iana.org/assignments/cbor-tags>.

   [IANA.core-parameters]
              IANA, "Constrained RESTful Environments (CoRE)
              Parameters", 8 June 2012,
              <https://www.iana.org/assignments/core-parameters>.

   [IANA.media-types]
              IANA, "Media Types", 13 July 2022,
              <https://www.iana.org/assignments/media-types>.

   [IANA.named-information]
              IANA, "Named Information", 14 August 2012,
              <https://www.iana.org/assignments/named-information>.

   [IANA.pa-tnc-parameters]
              IANA, "Posture Attribute (PA) Protocol Compatible with
              Trusted Network Connect (TNC) Parameters", 13 November
              2009,
              <https://www.iana.org/assignments/pa-tnc-parameters>.

   [IANA.uri-schemes]
              IANA, "Uniform Resource Identifier (URI) Schemes", 6 July
              2022, <https://www.iana.org/assignments/uri-schemes>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
              2003, <https://www.rfc-editor.org/info/rfc3629>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC5198]  Klensin, J. and M. Padlipsky, "Unicode Format for Network
              Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008,
              <https://www.rfc-editor.org/info/rfc5198>.






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   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
              Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
              September 2009, <https://www.rfc-editor.org/info/rfc5646>.

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, DOI 10.17487/RFC5890, August 2010,
              <https://www.rfc-editor.org/info/rfc5890>.

   [RFC7252]  Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
              Application Protocol (CoAP)", RFC 7252,
              DOI 10.17487/RFC7252, June 2014,
              <https://www.rfc-editor.org/info/rfc7252>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8288]  Nottingham, M., "Web Linking", RFC 8288,
              DOI 10.17487/RFC8288, October 2017,
              <https://www.rfc-editor.org/info/rfc8288>.

   [RFC8412]  Schmidt, C., Haynes, D., Coffin, C., Waltermire, D., and
              J. Fitzgerald-McKay, "Software Inventory Message and
              Attributes (SWIMA) for PA-TNC", RFC 8412,
              DOI 10.17487/RFC8412, July 2018,
              <https://www.rfc-editor.org/info/rfc8412>.

   [RFC8610]  Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
              Definition Language (CDDL): A Notational Convention to
              Express Concise Binary Object Representation (CBOR) and
              JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
              June 2019, <https://www.rfc-editor.org/info/rfc8610>.

   [RFC8949]  Bormann, C. and P. Hoffman, "Concise Binary Object
              Representation (CBOR)", STD 94, RFC 8949,
              DOI 10.17487/RFC8949, December 2020,
              <https://www.rfc-editor.org/info/rfc8949>.

   [SAM]      "Information technology - Software asset management - Part
              5: Overview and vocabulary", ISO/IEC 19770-5:2015, 15
              November 2013.




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   [SWID]     "Information technology - Software asset management - Part
              2: Software identification tag", ISO/IEC 19770-2:2015, 1
              October 2015.

   [UNSPSC]   "United Nations Standard Products and Services Code", 26
              October 2020, <https://www.unspsc.org/>.

   [W3C.REC-css3-mediaqueries-20120619]
              Rivoal, F., Ed., "Media Queries", W3C REC REC-css3-
              mediaqueries-20120619, W3C REC-css3-mediaqueries-20120619,
              19 June 2012, <https://www.w3.org/TR/2012/REC-css3-
              mediaqueries-20120619/>.

   [W3C.REC-xmlschema-2-20041028]
              Malhotra, A., Ed. and P. V. Biron, Ed., "XML Schema Part
              2: Datatypes Second Edition", W3C REC REC-xmlschema-
              2-20041028, W3C REC-xmlschema-2-20041028, 28 October 2004,
              <https://www.w3.org/TR/2004/REC-xmlschema-2-20041028/>.

   [W3C.REC-xpath20-20101214]
              Berglund, A., Ed., Chamberlin, D., Ed., Simeon, J., Ed.,
              Robie, J., Ed., Fernandez, M., Ed., Kay, M., Ed., and S.
              Boag, Ed., "XML Path Language (XPath) 2.0 (Second
              Edition)", W3C REC-xpath20-20101214, W3C REC REC-
              xpath20-20101214, 14 December 2010,
              <https://www.w3.org/TR/2010/REC-xpath20-20101214/>.

12.2.  Informative References

   [CamelCase]
              "UpperCamelCase", 29 August 2014,
              <http://wiki.c2.com/?CamelCase>.

   [I-D.ietf-rats-architecture]
              Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
              W. Pan, "Remote Attestation Procedures Architecture", Work
              in Progress, Internet-Draft, draft-ietf-rats-architecture-
              18, 14 June 2022, <https://www.ietf.org/archive/id/draft-
              ietf-rats-architecture-18.txt>.

   [KebabCase]
              "KebabCase", 18 December 2014,
              <http://wiki.c2.com/?KebabCase>.

   [RFC3444]  Pras, A. and J. Schoenwaelder, "On the Difference between
              Information Models and Data Models", RFC 3444,
              DOI 10.17487/RFC3444, January 2003,
              <https://www.rfc-editor.org/info/rfc3444>.



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   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122,
              DOI 10.17487/RFC4122, July 2005,
              <https://www.rfc-editor.org/info/rfc4122>.

   [RFC7595]  Thaler, D., Ed., Hansen, T., and T. Hardie, "Guidelines
              and Registration Procedures for URI Schemes", BCP 35,
              RFC 7595, DOI 10.17487/RFC7595, June 2015,
              <https://www.rfc-editor.org/info/rfc7595>.

   [RFC8322]  Field, J., Banghart, S., and D. Waltermire, "Resource-
              Oriented Lightweight Information Exchange (ROLIE)",
              RFC 8322, DOI 10.17487/RFC8322, February 2018,
              <https://www.rfc-editor.org/info/rfc8322>.

   [RFC8520]  Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
              Description Specification", RFC 8520,
              DOI 10.17487/RFC8520, March 2019,
              <https://www.rfc-editor.org/info/rfc8520>.

   [SEMVER]   Preston-Werner, T., "Semantic Versioning 2.0.0",
              <https://semver.org/spec/v2.0.0.html>.

   [SWID-GUIDANCE]
              Waltermire, D., Cheikes, B. A., Feldman, L., and G. Witte,
              "Guidelines for the Creation of Interoperable Software
              Identification (SWID) Tags", NISTIR 8060, April 2016,
              <https://doi.org/10.6028/NIST.IR.8060>.

   [X.1520]   "Recommendation ITU-T X.1520 (2014), Common
              vulnerabilities and exposures", 20 April 2011.

Acknowledgments

   This document draws heavily on the concepts defined in the ISO/IEC
   19770-2:2015 specification.  The authors of this document are
   grateful for the prior work of the 19770-2 contributors.

   We are also grateful for the careful reviews provided by the IESG
   reviewers.  Special thanks go to Benjamin Kaduk.

Contributors

   Carsten Bormann
   Universität Bremen TZI
   Postfach 330440
   D-28359 Bremen
   Germany



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   Phone: +49-421-218-63921
   Email: cabo@tzi.org


   Carsten Bormann contributed to the CDDL specifications and the IANA
   considerations.

Authors' Addresses

   Henk Birkholz
   Fraunhofer SIT
   Rheinstrasse 75
   64295 Darmstadt
   Germany
   Email: henk.birkholz@sit.fraunhofer.de


   Jessica Fitzgerald-McKay
   National Security Agency
   9800 Savage Road
   Ft. Meade, Maryland
   United States of America
   Email: jmfitz2@cyber.nsa.gov


   Charles Schmidt
   The MITRE Corporation
   202 Burlington Road
   Bedford, Massachusetts 01730
   United States of America
   Email: cmschmidt@mitre.org


   David Waltermire
   National Institute of Standards and Technology
   100 Bureau Drive
   Gaithersburg, Maryland 20877
   United States of America
   Email: david.waltermire@nist.gov












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