TEEP H. Tschofenig Internet-Draft H-BRS Intended status: Standards Track M. Pei Expires: 5 August 2026 Broadcom D. Wheeler Amazon D. Thaler Microsoft A. Tsukamoto Openchip & Software Technologies, S.L. 1 February 2026 Trusted Execution Environment Provisioning (TEEP) Protocol draft-ietf-teep-protocol-23 Abstract This document specifies a protocol that installs, updates, and deletes Trusted Components in a device with a Trusted Execution Environment (TEE). This specification defines an interoperable protocol for managing the lifecycle of Trusted Components. 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 5 August 2026. Copyright Notice Copyright (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved. 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. Tschofenig, et al. Expires 5 August 2026 [Page 1] Internet-Draft TEEP Protocol February 2026 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 . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Message Overview . . . . . . . . . . . . . . . . . . . . . . 5 4. Detailed Messages Specification . . . . . . . . . . . . . . . 6 4.1. Creating and Validating TEEP Messages . . . . . . . . . . 6 4.1.1. Creating a TEEP message . . . . . . . . . . . . . . . 7 4.1.2. Validating a TEEP Message . . . . . . . . . . . . . . 7 4.2. QueryRequest Message . . . . . . . . . . . . . . . . . . 8 4.3. QueryResponse Message . . . . . . . . . . . . . . . . . . 12 4.3.1. Evidence and Attestation Results . . . . . . . . . . 15 4.4. Update Message . . . . . . . . . . . . . . . . . . . . . 17 4.4.1. Scenario 1: Having one SUIT Manifest pointing to a URI of a Trusted Component Binary . . . . . . . . . . . . 20 4.4.2. Scenario 2: Having a SUIT Manifest include the Trusted Component Binary . . . . . . . . . . . . . . . . . . 23 4.4.3. Scenario 3: Supplying Personalization Data for the Trusted Component Binary . . . . . . . . . . . . . . 24 4.5. Success Message . . . . . . . . . . . . . . . . . . . . . 27 4.6. Error Message . . . . . . . . . . . . . . . . . . . . . . 28 5. EAT Profile . . . . . . . . . . . . . . . . . . . . . . . . . 32 5.1. Relationship to AR4SI . . . . . . . . . . . . . . . . . . 34 6. Mapping of TEEP Message Parameters to CBOR Labels . . . . . . 35 7. Behavior Specification . . . . . . . . . . . . . . . . . . . 37 7.1. TAM Behavior . . . . . . . . . . . . . . . . . . . . . . 37 7.1.1. Handling a QueryResponse Message . . . . . . . . . . 38 7.1.1.1. Handling an Attestation Result . . . . . . . . . 38 7.1.2. Handling a Success or Error Message . . . . . . . . . 40 7.2. TEEP Agent Behavior . . . . . . . . . . . . . . . . . . . 40 7.2.1. Handling a QueryRequest Message . . . . . . . . . . . 41 7.2.1.1. Handling an Attestation Result . . . . . . . . . 42 7.2.2. Handling an Update Message . . . . . . . . . . . . . 42 8. Cipher Suites . . . . . . . . . . . . . . . . . . . . . . . . 42 8.1. TEEP Messages . . . . . . . . . . . . . . . . . . . . . . 43 8.2. EATs and SUIT Reports . . . . . . . . . . . . . . . . . . 45 9. Attestation Freshness Mechanisms . . . . . . . . . . . . . . 47 10. Security Considerations . . . . . . . . . . . . . . . . . . . 48 10.1. Operational Considerations . . . . . . . . . . . . . . . 50 11. Transport Considerations . . . . . . . . . . . . . . . . . . 52 12. Privacy Considerations . . . . . . . . . . . . . . . . . . . 53 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 53 Tschofenig, et al. Expires 5 August 2026 [Page 2] Internet-Draft TEEP Protocol February 2026 13.1. Media Type Registration . . . . . . . . . . . . . . . . 53 13.2. TEEP Message Type Registry . . . . . . . . . . . . . . . 54 13.3. data-item-requested Bitmap Registry . . . . . . . . . . 55 13.4. TEEP Error Code Registry . . . . . . . . . . . . . . . . 56 13.5. TEEP CBOR Label Registry . . . . . . . . . . . . . . . . 58 13.6. TEEP Cipher Suite Registry . . . . . . . . . . . . . . . 60 13.7. TEEP Freshness Mechanism Registry . . . . . . . . . . . 60 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 61 14.1. Normative References . . . . . . . . . . . . . . . . . . 61 14.2. Informative References . . . . . . . . . . . . . . . . . 63 A. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 65 B. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 65 C. Complete CDDL . . . . . . . . . . . . . . . . . . . . . . . . 65 D. Examples of Diagnostic Notation and Binary Representation . . 70 D.1. QueryRequest Message . . . . . . . . . . . . . . . . . . 70 D.1.1. CBOR Diagnostic Notation . . . . . . . . . . . . . . 70 D.1.2. CBOR Binary Representation . . . . . . . . . . . . . 70 D.2. Entity Attestation Token . . . . . . . . . . . . . . . . 72 D.2.1. CBOR Diagnostic Notation . . . . . . . . . . . . . . 72 D.3. QueryResponse Message . . . . . . . . . . . . . . . . . . 72 D.3.1. CBOR Diagnostic Notation . . . . . . . . . . . . . . 72 D.3.2. CBOR Binary Representation . . . . . . . . . . . . . 73 D.4. Update Message . . . . . . . . . . . . . . . . . . . . . 74 D.4.1. CBOR Diagnostic Notation . . . . . . . . . . . . . . 74 D.4.2. CBOR Binary Representation . . . . . . . . . . . . . 76 D.5. Success Message . . . . . . . . . . . . . . . . . . . . . 77 D.5.1. CBOR Diagnostic Notation . . . . . . . . . . . . . . 77 D.5.2. CBOR Binary Representation . . . . . . . . . . . . . 77 D.6. Error Message . . . . . . . . . . . . . . . . . . . . . . 77 D.6.1. CBOR Diagnostic Notation . . . . . . . . . . . . . . 77 D.6.2. CBOR binary Representation . . . . . . . . . . . . . 77 E. Examples of SUIT Manifests . . . . . . . . . . . . . . . . . 78 Example 1: SUIT Manifest pointing to URI of the Trusted Component Binary . . . . . . . . . . . . . . . . . . . . . . . . 78 CBOR Diagnostic Notation of SUIT Manifest . . . . . . . . . . 78 CBOR Binary in Hex . . . . . . . . . . . . . . . . . . . . . 80 Example 2: SUIT Manifest including the Trusted Component Binary . . . . . . . . . . . . . . . . . . . . . . . . 80 CBOR Diagnostic Notation of SUIT Manifest . . . . . . . . . . 80 CBOR Binary in Hex . . . . . . . . . . . . . . . . . . . . . 82 Example 3: Supplying Personalization Data for Trusted Component Binary . . . . . . . . . . . . . . . . . . . . . . . . 82 CBOR Diagnostic Notation of SUIT Manifest . . . . . . . . . . 83 CBOR Binary in Hex . . . . . . . . . . . . . . . . . . . . . 86 F. Examples of SUIT Reports . . . . . . . . . . . . . . . . . . 86 F.1. Example 1: Success . . . . . . . . . . . . . . . . . . . 86 F.2. Example 2: Failure . . . . . . . . . . . . . . . . . . . 87 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 88 Tschofenig, et al. Expires 5 August 2026 [Page 3] Internet-Draft TEEP Protocol February 2026 1. Introduction The Trusted Execution Environment (TEE) concept has been designed to separate a regular operating system, also referred to as a Rich Execution Environment (REE), from security-sensitive applications. In a TEE ecosystem, device vendors may use different operating systems in the REE and may use different types of TEEs. When Trusted Component Developers or Device Administrators use Trusted Application Managers (TAMs) to install, update, and delete Trusted Applications and their dependencies on a wide range of devices with potentially different TEEs, then an interoperability need arises. This document specifies the protocol for communicating between a TAM and a TEEP Agent. The Trusted Execution Environment Provisioning (TEEP) architecture document [RFC9397] provides design guidance and introduces the necessary terminology. 2. Terminology 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. This specification reuses the terminology defined in [RFC9397]. As explained in Section 4.4 of that document, the TEEP protocol treats each Trusted Application (TA), any dependencies the TA has, and personalization data as separate components that are expressed in SUIT manifests, and a SUIT manifest might contain or reference multiple binaries (see [I-D.ietf-suit-manifest] for more details). As such, the term Trusted Component (TC) in this document refers to a set of binaries expressed in a SUIT manifest, to be installed in a TEE. Note that a Trusted Component may include one or more TAs and/ or configuration data and keys needed by a TA to operate correctly. Each Trusted Component is uniquely identified by a SUIT Component Identifier (see [I-D.ietf-suit-manifest] Section 8.7.2.2). Attestation related terms, such as Evidence and Attestation Results, are as defined in [RFC9334]. Tschofenig, et al. Expires 5 August 2026 [Page 4] Internet-Draft TEEP Protocol February 2026 3. Message Overview The TEEP protocol consists of messages exchanged between a TAM and a TEEP Agent. The messages are encoded in CBOR and designed to provide end-to-end security. TEEP protocol messages are signed by the endpoints, i.e., the TAM and the TEEP Agent, but Trusted Applications may also be encrypted and signed by a Trusted Component Developer or Device Administrator. The TEEP protocol not only uses CBOR but also the respective security wrapper, namely COSE [RFC9052]. Furthermore, for software updates the SUIT manifest format [I-D.ietf-suit-manifest] is used, and for attestation the Entity Attestation Token (EAT) [RFC9711] format is supported although other attestation formats are also permitted. This specification defines five messages: QueryRequest, QueryResponse, Update, Success, and Error. A TAM queries a device's current state with a QueryRequest message. A TEEP Agent will, after authenticating and authorizing the request, report attestation information, list all Trusted Components, and provide information about supported algorithms and extensions in a QueryResponse message. An error message is returned if the request could not be processed. A TAM will process the QueryResponse message and determine whether to initiate subsequent message exchanges to install, update, or delete Trusted Applications. +------------+ +-------------+ | TAM | |TEEP Agent | +------------+ +-------------+ QueryRequest -------> QueryResponse <------- or Error With the Update message a TAM can instruct a TEEP Agent to install and/or delete one or more Trusted Components. The TEEP Agent will process the message, determine whether the TAM is authorized and whether the Trusted Component has been signed by an authorized Trusted Component Signer. A Success message is returned when the operation has been completed successfully, or an Error message otherwise. Tschofenig, et al. Expires 5 August 2026 [Page 5] Internet-Draft TEEP Protocol February 2026 +------------+ +-------------+ | TAM | |TEEP Agent | +------------+ +-------------+ Update ----> Success <---- or Error 4. Detailed Messages Specification TEEP messages are protected by the COSE_Sign1 or COSE_Sign structure as described in Section 8.1. The TEEP protocol messages are described in CDDL format [RFC8610] below. teep-message = $teep-message-type .within teep-message-framework teep-message-framework = [ type: $teep-type / $teep-type-extension, options: { * teep-option }, * any; further elements, e.g., for data-item-requested ] teep-option = (uint => any) ; messages defined below: $teep-message-type /= query-request $teep-message-type /= query-response $teep-message-type /= update $teep-message-type /= teep-success $teep-message-type /= teep-error ; message type numbers, in one byte which could take a ; number from 0 to 23 $teep-type /= (0..23) TEEP-TYPE-query-request = 1 TEEP-TYPE-query-response = 2 TEEP-TYPE-update = 3 TEEP-TYPE-teep-success = 5 TEEP-TYPE-teep-error = 6 4.1. Creating and Validating TEEP Messages Tschofenig, et al. Expires 5 August 2026 [Page 6] Internet-Draft TEEP Protocol February 2026 4.1.1. Creating a TEEP message To create a TEEP message, the following steps are performed. 1. Create a TEEP message according to the description below and populate it with the respective content. TEEP messages sent by TAMs (QueryRequest and Update) can include a "token". The TAM can decide, in any implementation-specific way, whether to include a token in a message. The initial token value generated by a TAM MUST be produced using a cryptographically secure random source. Subsequent token values MUST be different for each message the TAM creates. 2. Create a COSE header containing the desired set of header parameters. The COSE header MUST be valid per the [RFC9052] specification. 3. Create a COSE_Sign1 or COSE_Sign object using the TEEP message as the COSE_Sign1 or COSE_Sign Payload; all steps specified in [RFC9052] for creating a COSE_Sign1 or COSE_Sign object MUST be followed. 4.1.2. Validating a TEEP Message When a TEEP message is received (see the ProcessTeepMessage conceptual API defined in Section 6.2.1 of [RFC9397]), the following validation steps are performed. If any of the listed steps fail, then the TEEP message MUST be rejected. 1. Verify that the received message is a valid CBOR object. 2. Verify that the message contains a COSE_Sign1 or COSE_Sign structure. 3. Verify that the resulting COSE header includes only parameters and values whose syntax and semantics are both understood and supported or that are specified as being ignored when not understood. 4. Follow the steps specified in Section 4 of [RFC9052] ("Signing Objects") for validating a COSE_Sign1 or COSE_Sign object. The COSE_Sign1 or COSE_Sign payload is the content of the TEEP message. 5. Verify that the TEEP message is a valid CBOR map and verify the fields of the TEEP message according to this specification. Tschofenig, et al. Expires 5 August 2026 [Page 7] Internet-Draft TEEP Protocol February 2026 4.2. QueryRequest Message A QueryRequest message is used by the TAM to learn information from the TEEP Agent, such as the features supported by the TEEP Agent, including cipher suites and protocol versions. Additionally, the TAM can selectively request data items from the TEEP Agent by using the data-item-requested parameter. Currently, the following features are supported: * Request for attestation information of the TEEP Agent, * Listing supported extensions, * Querying installed Trusted Components, and * Request for logging information in SUIT Reports. Like other TEEP messages, the QueryRequest message is signed, and the relevant CDDL snippet is shown below. The complete CDDL structure is shown in Appendix C. Tschofenig, et al. Expires 5 August 2026 [Page 8] Internet-Draft TEEP Protocol February 2026 query-request = [ type: TEEP-TYPE-query-request, options: { ? token => bstr .size (8..64), ? supported-freshness-mechanisms => [ + $freshness-mechanism ], ? challenge => bstr .size (8..512), ? versions => [ + version ], ? attestation-payload-format => text, ? attestation-payload => bstr, ? suit-reports => [ + bstr .cbor SUIT_Report ], * $$query-request-extensions, * $$teep-option-extensions }, supported-teep-cipher-suites: [ + $teep-cipher-suite ], supported-suit-cose-profiles: [ + $suit-cose-profile ], data-item-requested: uint .bits data-item-requested ] version = uint .size 4 ext-info = uint .size 4 ; data items as bitmaps data-item-requested = &( attestation: 0, trusted-components: 1, extensions: 2, suit-reports: 3, ) The message has the following fields: type The value of (1) corresponds to a QueryRequest message sent from the TAM to the TEEP Agent. token The value in the token parameter is used to match responses to requests, such as to look up any implementation-specific state it might have saved about that request, or to ignore responses to older QueryRequest messages before some configuration changes were made that affected their content. This is particularly useful when a TAM issues multiple concurrent requests to a TEEP Agent. The token MUST be present if and only if the attestation bit is clear in the data-item-requested value (i.e., the attestation bit, which is bit 0 in the bitmap, is not set). When the attestation bit is clear then a challenge will be included, which offers replay protection capabilities. The size of the token is at least 8 bytes (64 bits) and maximum of 64 bytes. The first usage of a Tschofenig, et al. Expires 5 August 2026 [Page 9] Internet-Draft TEEP Protocol February 2026 token generated by a TAM MUST be randomly created. Subsequent token values MUST be different for each request message to distinguish the correct response from multiple requests. The token value MUST NOT be used for other purposes, such as a TAM to identify the devices and/or a device to identify TAMs or Trusted Components. The TAM SHOULD set an expiration time for each token to facilitate cleanup of stale request state, and MUST ignore any messages with expired tokens. Implementations without explicit token management (e.g., simple TAMs that process requests synchronously and do not maintain state) may not need explicit token expiration. The TAM MUST expire the token value after receiving the first response containing the token value and ignore any subsequent messages that have the same token value. Implementations SHOULD use a timeout mechanism (see Section 7.1) to eventually discard unanswered requests that have been awaiting responses for an excessive duration. supported-teep-cipher-suites The supported-teep-cipher-suites parameter lists the TEEP cipher suites supported by the TAM. Details about the cipher suite encoding can be found in Section 8.1. supported-suit-cose-profiles The supported-suit-cose-profiles parameter lists the SUIT profiles supported by the TAM for parsing SUIT Reports. Details about the cipher suite encoding can be found in Section 8.2. data-item-requested The data-item-requested parameter indicates what information the TAM requests from the TEEP Agent in the form of a bitmap. attestation (1): With this value the TAM requests the TEEP Agent to return an attestation payload, whether Evidence (e.g., an EAT) or an Attestation Result, in the response. trusted-components (2): With this value the TAM queries the TEEP Agent for all installed Trusted Components. extensions (4): With this value the TAM queries the TEEP Agent for supported capabilities and extensions, which allows a TAM to discover the capabilities of a TEEP Agent implementation. suit-reports (8): With this value the TAM requests the TEEP Agent to return SUIT Reports in the response. Further values may be added in the future. supported-freshness-mechanisms Tschofenig, et al. Expires 5 August 2026 [Page 10] Internet-Draft TEEP Protocol February 2026 The supported-freshness-mechanisms parameter lists the freshness mechanism(s) supported by the TAM. Details about the encoding can be found in Section 9. If this parameter is absent, it means only the nonce mechanism is supported. It MUST be absent if the attestation bit is clear. challenge The challenge field is an optional parameter used for ensuring the freshness of attestation Evidence returned with a QueryResponse message. It MUST be absent if the attestation bit is clear or the Passport model (see [RFC9334]) is used. When a challenge is provided in the QueryRequest and Evidence in the form of an EAT is returned with a QueryResponse message then the challenge contained in the QueryRequest MUST be used to generate the EAT, by copying the challenge into the eat_nonce claim (Section 4.1 of [RFC9711]) if the nonce-based freshness mechanism is used for attestation Evidence. For more details about freshness of Evidence see Section 9. If any format other than EAT is used, it is up to that format to define the use of the challenge field. versions The versions parameter enumerates the TEEP protocol version(s) supported by the TAM. A value of 0 refers to the version of the TEEP protocol defined in this document. If this field is not present, it is to be treated the same as if it contained only version 0. attestation-payload-format The attestation-payload-format parameter indicates the IANA Media Type of the attestation-payload parameter, where media type parameters are permitted after the media type. For protocol version 0, the absence of this parameter indicates that the format is "application/eat+cwt; eat_profile=urn:ietf:rfc:rfcXXXX" (see [RFC9782] for further discussion). (RFC-editor: upon RFC publication, replace XXXX above with the RFC number of this document.) It MUST be present if the attestation-payload parameter is present and the format is not an EAT in CWT format with the profile defined below in Section 5. attestation-payload Tschofenig, et al. Expires 5 August 2026 [Page 11] Internet-Draft TEEP Protocol February 2026 The attestation-payload parameter contains Evidence or an Attestation Result for the TEEP Agent to use to perform attestation of the TAM. If the attestation-payload-format parameter is absent, the attestation payload contained in this parameter MUST be an Entity Attestation Token following the encoding defined in [RFC9711]. See Section 4.3.1 for further discussion. suit-reports If present, the suit-reports parameter contains a set of TAM SUIT Reports related to “boot” time (including the start of an executable in an OS context), as defined by SUIT_Report in Section 4 of [I-D.ietf-suit-report]. SUIT Reports are encoded as CBOR byte strings. When a SUIT Report includes its own COSE protection (via signatures or MACs), the cryptographic key used MUST be distinct from the key used for the TEEP message's COSE security wrapper since otherwise its authenticity relies on the TEEP message's signature/MAC keys without adding any additional security. SUIT Reports can be useful in QueryRequest messages to pass additional information about the TAM to the TEEP Agent without depending on a Verifier including the relevant information in the TAM's Attestation Results. 4.3. QueryResponse Message The QueryResponse message is the successful response by the TEEP Agent after receiving a QueryRequest message. As discussed in Section 7.2, it can also be sent unsolicited if the contents of the QueryRequest are already known and do not vary per message. Like other TEEP messages, the QueryResponse message is signed, and the relevant CDDL snippet is shown below. The complete CDDL structure is shown in Appendix C. Tschofenig, et al. Expires 5 August 2026 [Page 12] Internet-Draft TEEP Protocol February 2026 query-response = [ type: TEEP-TYPE-query-response, options: { ? token => bstr .size (8..64), ? selected-version => version, ? attestation-payload-format => text, ? attestation-payload => bstr, ? suit-reports => [ + bstr .cbor SUIT_Report ], ? tc-list => [ + system-property-claims ], ? requested-tc-list => [ + requested-tc-info ], ? unneeded-manifest-list => [ + SUIT_Component_Identifier ], ? ext-list => [ + ext-info ], * $$query-response-extensions, * $$teep-option-extensions } ] requested-tc-info = { component-id => SUIT_Component_Identifier, ? tc-manifest-sequence-number => uint, ? have-binary => bool } The QueryResponse message has the following fields: type The value of (2) corresponds to a QueryResponse message sent from the TEEP Agent to the TAM. token The value in the token parameter is used to match responses to requests. The value MUST correspond to the value received with the QueryRequest message if one was present, and MUST be absent if no token was present in the QueryRequest. selected-version The selected-version parameter indicates the TEEP protocol version selected by the TEEP Agent. The absence of this parameter indicates the same as if it was present with a value of 0. attestation-payload-format The attestation-payload-format parameter indicates the IANA Media Type of the attestation-payload parameter, where media type parameters are permitted after the media type. For protocol version 0, the absence of this parameter indicates that the format is "application/eat+cwt; eat_profile=urn:ietf:rfc:rfcXXXX" (see [RFC9782] for further discussion). (RFC-editor: upon RFC publication, replace XXXX above with the RFC number of this Tschofenig, et al. Expires 5 August 2026 [Page 13] Internet-Draft TEEP Protocol February 2026 document.) It MUST be present if the attestation-payload parameter is present and the format is not an EAT in CWT format with the profile defined below in Section 5. attestation-payload The attestation-payload parameter contains Evidence or an Attestation Result. This parameter MUST be present if the QueryResponse is sent in response to a QueryRequest with the attestation bit set. If the attestation-payload-format parameter is absent, the attestation payload contained in this parameter MUST be an Entity Attestation Token following the encoding defined in [RFC9711]. See Section 4.3.1 for further discussion. suit-reports If present, the suit-reports parameter contains a set of "boot" (including starting an executable in an OS context) time SUIT Reports as defined by SUIT_Report in Section 4 of [I-D.ietf-suit-report], encoded using COSE as discussed in Section 8.2. If a token parameter was present in the QueryRequest message the QueryResponse message is in response to, the suit- report-nonce field MUST be present in the SUIT Report with a value matching the token parameter in the QueryRequest message. SUIT Reports can be useful in QueryResponse messages to pass information to the TAM without depending on a Verifier including the relevant information in Attestation Results. tc-list The tc-list parameter enumerates the Trusted Components installed on the device in the form of system-property-claims objects, as defined in Section 4 of [I-D.ietf-suit-report]. The system- property-claims can be used to learn device identifying information and TEE identifying information for distinguishing which Trusted Components to install in the TEE. This parameter MUST be present if the QueryResponse is sent in response to a QueryRequest with the trusted-components bit set. requested-tc-list The requested-tc-list parameter enumerates the Trusted Components that are not currently installed in the TEE, but which are requested to be installed, for example by an installer of an Untrusted Application that has a TA as a dependency, or by a Trusted Application that has another Trusted Component as a dependency. Requested Trusted Components are expressed in the form of requested-tc-info objects. A TEEP Agent can get this information from the RequestTA conceptual API defined in [RFC9397] Section 6.2.1. unneeded-manifest-list Tschofenig, et al. Expires 5 August 2026 [Page 14] Internet-Draft TEEP Protocol February 2026 The unneeded-manifest-list parameter enumerates the SUIT manifests whose components are currently installed in the TEE, but which are no longer needed by any other application. The TAM can use this information in determining whether a SUIT manifest can be unlinked. Each unneeded SUIT manifest is identified by its SUIT Manifest Component ID (note that this is the Component ID for the manifest itself, which is different from the Component ID of a component installed by the manifest, see [I-D.ietf-suit-trust-domains] for more discussion). A TEEP Agent can get this information from the UnrequestTA conceptual API defined in [RFC9397] Section 6.2.1. ext-list The ext-list parameter lists the supported extensions. This document does not define any extensions. This parameter MUST be present if the QueryResponse is sent in response to a QueryRequest with the extensions bit set. The requested-tc-info message has the following fields: component-id A SUIT Component Identifier; see [RFC9124]. tc-manifest-sequence-number The minimum suit-manifest-sequence-number value from a SUIT manifest for the Trusted Component. If not present, indicates that any sequence number will do. have-binary If present with a value of true, indicates that the TEEP Agent already has the Trusted Component binary and only needs an Update message with a SUIT manifest that authorizes installing it. If have-binary is true, the tc-manifest-sequence-number field MUST be present. 4.3.1. Evidence and Attestation Results Section 7 of [RFC9397] lists information that may appear in Evidence depending on the circumstance. However, the Evidence is opaque to the TEEP protocol and there are no formal requirements on the contents of Evidence. TAMs consume Attestation Results and do need enough information therein to make decisions on how to remediate a TEE that is out of compliance, or update a TEE that is requesting an authorized change. To do so, the information in Section 7 of [RFC9397] is often required depending on the policy. Tschofenig, et al. Expires 5 August 2026 [Page 15] Internet-Draft TEEP Protocol February 2026 Attestation Results SHOULD use Entity Attestation Tokens (EATs) to use a standardized format and to reduce TAM implementation complexity. Use of any other format, such as a widely implemented format for a specific processor vendor, is permitted when standardized EAT support is not available or when proprietary formats provide essential functionality, but this increases the complexity of the TAM by requiring it to understand the format for each such format rather than only the common EAT format and is not recommended for interoperable deployments. When an EAT is used, the following claims can be used to meet those requirements, whether these claims appear in Attestation Results, or in Evidence for the Verifier to use when generating Attestation Results of some form: +==========================+===========+============================+ | Requirement | Claim | Reference | +==========================+===========+============================+ | Freshness proof | nonce | Section 4.1 of [RFC9711] | +--------------------------+-----------+----------------------------+ | Device unique identifier | ueid | Section 4.2.1 of | | | | [RFC9711] | +--------------------------+-----------+----------------------------+ | Vendor of the device | oemid | Section 4.2.3 of | | | | [RFC9711] | +--------------------------+-----------+----------------------------+ | Class of the device | hwmodel | Section 4.2.4 of | | | | [RFC9711] | +--------------------------+-----------+----------------------------+ | TEE hardware type | hwversion | Section 4.2.5 of | | | | [RFC9711] | +--------------------------+-----------+----------------------------+ | TEE hardware version | hwversion | Section 4.2.5 of | | | | [RFC9711] | +--------------------------+-----------+----------------------------+ | TEE firmware type | manifests | Section 4.2.15 of | | | | [RFC9711] | +--------------------------+-----------+----------------------------+ | TEE firmware version | manifests | Section 4.2.15 of | | | | [RFC9711] | +--------------------------+-----------+----------------------------+ Table 1 The "manifests" claim (see Section 4.2.15 of [RFC9711]) should include information about the TEEP Agent as well as any of its dependencies such as firmware. Tschofenig, et al. Expires 5 August 2026 [Page 16] Internet-Draft TEEP Protocol February 2026 4.4. Update Message The Update message is used by the TAM to install and/or delete one or more Trusted Components via the TEEP Agent. It can also be used to pass a successful Attestation Report back to the TEEP Agent when the TAM is configured as an intermediary between the TEEP Agent and a Verifier, as shown in Figure 1, where the Attestation Result passed back to the Attester can be used as a so-called "passport" (see Section 5.1 of [RFC9334]) that can be presented to other Relying Parties. +---------------+ | Verifier | +---------------+ ^ | Attestation Evidence | v Result +---------------+ | TAM / | | Relying Party | +---------------+ QueryResponse ^ | Update (Evidence) | | (Attestation | v Result) +---------------+ +---------------+ | TEEP Agent |------------>| Other | | / Attester | Attestation | Relying Party | +---------------+ Result +---------------+ Figure 1: Example use of TEEP and Attestation. Like other TEEP messages, the Update message is signed, and the relevant CDDL snippet is shown below. The complete CDDL structure is shown in Appendix C. Tschofenig, et al. Expires 5 August 2026 [Page 17] Internet-Draft TEEP Protocol February 2026 update = [ type: TEEP-TYPE-update, options: { ? token => bstr .size (8..64), ? unneeded-manifest-list => [ + SUIT_Component_Identifier ], ? manifest-list => [ + bstr .cbor SUIT_Envelope ], ? attestation-payload-format => text, ? attestation-payload => bstr, ? err-code => (0..23), ? err-msg => text .size (1..128), ? err-lang => text .size (1..35), * $$update-extensions, * $$teep-option-extensions } ] The Update message has the following fields: type The value of (3) corresponds to an Update message sent from the TAM to the TEEP Agent. In case of successful processing, a Success message is returned by the TEEP Agent. In case of an error, an Error message is returned. Note that the Update message is used for initial Trusted Component installation as well as for updates and deletes. token The value in the token field is used to match responses to requests. unneeded-manifest-list The unneeded-manifest-list parameter enumerates the SUIT manifests to be unlinked. Each unneeded SUIT manifest is identified by its SUIT Manifest Component ID. The SUIT manifest processor MAY execute uninstall section in the manifest. See Section 7 of [I-D.ietf-suit-trust-domains] for more information about the suit- uninstall Command Sequence. manifest-list Tschofenig, et al. Expires 5 August 2026 [Page 18] Internet-Draft TEEP Protocol February 2026 The manifest-list field is used to convey one or multiple SUIT manifests to install. A manifest is a bundle of metadata about a Trusted Component, such as where to find the code, the devices to which it applies, and cryptographic information protecting the manifest. The manifest may also convey personalization data. Trusted Component binaries and personalization data can be signed and encrypted by the same Trusted Component Signer. Other combinations are, however, possible as well. For example, it is also possible for the TAM to sign and encrypt the personalization data and to let the Trusted Component Developer sign and/or encrypt the Trusted Component binary. attestation-payload-format The attestation-payload-format parameter indicates the IANA Media Type of the attestation-payload parameter, where media type parameters are permitted after the media type. The absence of this parameter indicates that the format is "application/eat+cwt; eat_profile=urn:ietf:rfc:rfcXXXX" (see [RFC9782] for further discussion). (RFC-editor: upon RFC publication, replace XXXX above with the RFC number of this document.) It MUST be present if the attestation-payload parameter is present and the format is not an EAT in CWT format with the profile defined in Section 5. attestation-payload The attestation-payload parameter contains an Attestation Result. If the attestation-payload-format parameter is absent, the attestation payload contained in this parameter MUST be an Entity Attestation Token following the encoding defined in [RFC9711]. See Section 4.3.1 for further discussion. err-code The err-code parameter contains one of the error codes listed in the Section 4.6, which describes the reasons for the error when performing QueryResponse in the TAM. err-msg The err-msg parameter is human-readable diagnostic text that MUST be encoded using UTF-8 [RFC3629] in Net-Unicode format [RFC5198] with a maximum of 128 bytes. err-lang The err-lang parameter is an OPTIONAL RFC 5646 [RFC5646] language tag identifying the language of the err-msg text. When present, implementations MUST use the language tag to aid human operators in interpreting diagnostic text. The err-msg field SHOULD be formatted in the language indicated by this tag. Tschofenig, et al. Expires 5 August 2026 [Page 19] Internet-Draft TEEP Protocol February 2026 Note that an Update message carrying one or more SUIT manifests will inherently involve multiple signatures, one by the TAM in the TEEP message and one from a Trusted Component Signer inside each manifest. This is intentional as they are for different purposes. The TAM is what authorizes apps to be installed, updated, and deleted on a given TEE and so the TEEP signature is checked by the TEEP Agent at protocol message processing time. (This same TEEP security wrapper is also used on messages like QueryRequest so that Agents only send potentially sensitive data such as Evidence to trusted TAMs.) The Trusted Component signer, on the other hand, is what authorizes the Trusted Component to actually run, so the manifest signature could be checked at install time, load (or run) time, or both, and this checking is done by the TEE independent of whether TEEP is used or some other update mechanism. See Section 5 of [RFC9397] for further discussion. The Update message has a SUIT_Envelope containing SUIT manifests. Following are some example scenarios using SUIT manifests in the Update Message. 4.4.1. Scenario 1: Having one SUIT Manifest pointing to a URI of a Trusted Component Binary In this scenario, a SUIT Manifest has a URI pointing to a Trusted Component Binary. A Trusted Component Developer creates a new Trusted Component Binary and hosts it at a Trusted Component Developer's URI. Then, the Trusted Component Developer generates an associated SUIT manifest with the filename "tc-uuid" that contains the URI. The filename "tc- uuid" is used in Scenario 3 later. The TAM receives the latest SUIT manifest from the Trusted Component Developer, and the URI it contains cannot be changed by the TAM since the SUIT manifest is signed by the Trusted Component Developer. Figure 2 shows the exchange graphically. Pros: * The Trusted Component Developer can ensure that the intact Trusted Component Binary is downloaded by devices * The TAM does not have to send large Update messages containing the Trusted Component Binary Tschofenig, et al. Expires 5 August 2026 [Page 20] Internet-Draft TEEP Protocol February 2026 Cons: * The Trusted Component Developer must host the Trusted Component Binary server * The device must fetch the Trusted Component Binary in another connection after receiving an Update message * A device's IP address and therefore location may be revealed to the Trusted Component Binary server Tschofenig, et al. Expires 5 August 2026 [Page 21] Internet-Draft TEEP Protocol February 2026 +------------+ +-------------+ | TAM | | TEEP Agent | +------------+ +-------------+ Update ----> +=================== teep-protocol(TAM) ==================+ | TEEP_Message([ | | TEEP-TYPE-update, | | options: { | | manifest-list: [ | | += suit-manifest "tc-uuid" (TC Developer) ======+ | | | SUIT_Envelope({ | | | | manifest: { | | | | install: { | | | | override-parameters: { | | | | uri: "https://example.org/tc-uuid.ta" | | | | }, | | | | fetch | | | | } | | | | } | | | | }) | | | +===============================================+ | | ] | | } | | ]) | +=========================================================+ and then, +-------------+ +--------------+ | TEEP Agent | | TC Developer | +-------------+ +--------------+ <---- fetch "https://example.org/tc-uuid.ta" +======= tc-uuid.ta =======+ | 48 65 6C 6C 6F 2C 20 ... | +==========================+ Figure 2: URI of the Trusted Component Binary. For the full SUIT Manifest example binary, see Appendix "Example 1: SUIT Manifest pointing to URI of the Trusted Component Binary". Tschofenig, et al. Expires 5 August 2026 [Page 22] Internet-Draft TEEP Protocol February 2026 4.4.2. Scenario 2: Having a SUIT Manifest include the Trusted Component Binary In this scenario, the SUIT manifest contains the entire Trusted Component Binary as an integrated payload (see [I-D.ietf-suit-manifest] Section 7.5). A Trusted Component Developer delegates the task of delivering the Trusted Component Binary to the TAM inside the SUIT manifest. The Trusted Component Developer creates a SUIT manifest and embeds the Trusted Component Binary, which is referenced in the suit-integrated- payload element containing the fragment-only reference "#tc", in the envelope. The Trusted Component Developer transmits the entire bundle to the TAM. The TAM serves the SUIT manifest containing the Trusted Component Binary to the device in an Update message. Figure 3 shows the exchange graphically. Pros: * The device can obtain the Trusted Component Binary and the SUIT manifest in one Update message. * The Trusted Component Developer does not have to host a server to deliver the Trusted Component Binary to devices. Cons: * The TAM must host the Trusted Component Binary rather than delegating storage to the Trusted Component Developer. * The TAM must deliver Trusted Component Binaries in Update messages, which increases the size of the Update message. Tschofenig, et al. Expires 5 August 2026 [Page 23] Internet-Draft TEEP Protocol February 2026 +------------+ +-------------+ | TAM | | TEEP Agent | +------------+ +-------------+ Update ----> +=========== teep-protocol(TAM) ============+ | TEEP_Message([ | | TEEP-TYPE-update, | | options: { | | manifest-list: [ | | +== suit-manifest(TC Developer) ==+ | | | SUIT_Envelope({ | | | | manifest: { | | | | install: { | | | | override-parameters: { | | | | uri: "#tc" | | | | }, | | | | fetch | | | | } | | | | }, | | | | "#tc": h'48 65 6C 6C ...' | | | | }) | | | +=================================+ | | ] | | } | | ]) | +===========================================+ Figure 3: Integrated Payload with Trusted Component Binary. For the full SUIT Manifest example binary, see Appendix "Example 2: SUIT Manifest including the Trusted Component Binary". 4.4.3. Scenario 3: Supplying Personalization Data for the Trusted Component Binary In this scenario, Personalization Data is associated with the Trusted Component Binary "tc-uuid" from Scenario 1. The Trusted Component Developer places encrypted Personalization Data in the SUIT manifest, and it will be delivered by the TAM. The SUIT manifest processor decrypts it, then stores it in a file named "config.json", and then installs the dependency component. The TAM delivers the SUIT manifest of the Personalization Data which depends on the Trusted Component Binary from Scenario 1. Tschofenig, et al. Expires 5 August 2026 [Page 24] Internet-Draft TEEP Protocol February 2026 Figure 4 shows the exchange graphically. Tschofenig, et al. Expires 5 August 2026 [Page 25] Internet-Draft TEEP Protocol February 2026 +------------+ +-------------+ | TAM | | TEEP Agent | +------------+ +-------------+ Update ----> +================== teep-protocol(TAM) ======================+ | TEEP_Message([ | | TEEP-TYPE-update, | | options: { | | manifest-list: [ | | +========= suit-manifest(TC Developer) ============+ | | | SUIT_Envelope({ | | | | manifest: { | | | | common: { | | | | dependencies: { | | | | dependency-prefix 1: { | | | | [tc-uuid, 'suit'] | | | | } | | | | } | | | | components: [ | | | | ['config.json'] | | | | ] | | | | }, | | | | dependency-resolution: { | | | | override-parameters: { | | | | uri: "https://example.org/tc-uuid" | | | | }, | | | | fetch | | | | }, | | | | install: { | | | | set-component-index 0, | | | | override-parameters: { | | | | content: h'48FE0794...' | | | | encryption-info: << ... >> | | | | }, | | | | write, | | | | set-component-index 1, | | | | process-dependency | | | | } | | | | } | | | | }) | | | +==================================================+ | | ] | | } | | ]) | +============================================================+ Tschofenig, et al. Expires 5 August 2026 [Page 26] Internet-Draft TEEP Protocol February 2026 Figure 4: Encrypted Personalization Data. For the full SUIT Manifest example binary, see Appendix "Example 3: Supplying Personalization Data for Trusted Component Binary". 4.5. Success Message The Success message is used by the TEEP Agent to return a success in response to an Update message. Like other TEEP messages, the Success message is signed, and the relevant CDDL snippet is shown below. The complete CDDL structure is shown in Appendix C. teep-success = [ type: TEEP-TYPE-teep-success, options: { ? token => bstr .size (8..64), ? msg => text .size (1..128), ? suit-reports => [ + bstr .cbor SUIT_Report ], * $$teep-success-extensions, * $$teep-option-extensions } ] The Success message has the following fields: type The value of (5) corresponds to a Success message sent from the TEEP Agent to the TAM. token The value in the token parameter is used to match responses to requests. It MUST match the value of the token parameter in the Update message the Success is in response to, if one was present. If none was present, the token MUST be absent in the Success message. msg The msg parameter contains optional diagnostics information encoded in UTF-8 [RFC3629] using Net-Unicode form [RFC5198] with max 128 bytes returned by the TEEP Agent. suit-reports If present, the suit-reports parameter contains a set of SUIT Reports as defined in Section 4 of [I-D.ietf-suit-report], encoded as CBOR byte strings containing either protected or unprotected SUIT Report payloads. When a SUIT Report includes its own COSE Tschofenig, et al. Expires 5 August 2026 [Page 27] Internet-Draft TEEP Protocol February 2026 protection (signatures or MACs), the cryptographic key used MUST be distinct from the key used for the TEEP message's COSE security wrapper. If a token parameter was present in the Update message the Success message is in response to, the suit-report-nonce field MUST be present in the SUIT Report with a value matching the token parameter in the Update message. 4.6. Error Message The Error message is used by the TEEP Agent to return an error in response to a message from the TAM. Like other TEEP messages, the Error message is signed, and the relevant CDDL snippet is shown below. The complete CDDL structure is shown in Appendix C. teep-error = [ type: TEEP-TYPE-teep-error, options: { ? token => bstr .size (8..64), ? err-msg => text .size (1..128), ? err-lang => text .size (1..35), ? supported-teep-cipher-suites => [ + $teep-cipher-suite ], ? supported-freshness-mechanisms => [ + $freshness-mechanism ], ? supported-suit-cose-profiles => [ + $suit-cose-profile ], ? challenge => bstr .size (8..512), ? versions => [ + version ], ? suit-reports => [ + bstr .cbor SUIT_Report ], * $$teep-error-extensions, * $$teep-option-extensions }, err-code: (0..23) ] ; The err-code parameter, uint (0..23) ERR_PERMANENT_ERROR = 1 ERR_UNSUPPORTED_EXTENSION = 2 ERR_UNSUPPORTED_FRESHNESS_MECHANISMS = 3 ERR_UNSUPPORTED_MSG_VERSION = 4 ERR_UNSUPPORTED_CIPHER_SUITES = 5 ERR_BAD_CERTIFICATE = 6 ERR_ATTESTATION_REQUIRED = 7 ERR_UNSUPPORTED_SUIT_REPORT = 8 ERR_CERTIFICATE_EXPIRED = 9 ERR_TEMPORARY_ERROR = 10 ERR_MANIFEST_PROCESSING_FAILED = 17 The Error message has the following fields: Tschofenig, et al. Expires 5 August 2026 [Page 28] Internet-Draft TEEP Protocol February 2026 type The value of (6) corresponds to an Error message sent from the TEEP Agent to the TAM. token The value in the token parameter is used to match responses to requests. It MUST match the value of the token parameter in the message the Success is in response to, if one was present. If none was present, the token MUST be absent in the Error message. err-msg The err-msg parameter is human-readable diagnostic text that MUST be encoded using UTF-8 [RFC3629] using Net-Unicode form [RFC5198] with max 128 bytes. err-lang The err-lang parameter is an OPTIONAL RFC 5646 [RFC5646] language tag identifying the language of the err-msg text. When present, implementations SHOULD use the language tag to aid human operators in interpreting diagnostic text. The err-msg field SHOULD be formatted in the language indicated by this tag. supported-teep-cipher-suites The supported-teep-cipher-suites parameter lists the TEEP cipher suite(s) supported by the TEEP Agent. Details about the cipher suite encoding can be found in Section 8.1. This otherwise optional parameter MUST be returned if err-code is ERR_UNSUPPORTED_CIPHER_SUITES. supported-freshness-mechanisms The supported-freshness-mechanisms parameter lists the freshness mechanism(s) supported by the TEEP Agent. Details about the encoding can be found in Section 9. This otherwise optional parameter MUST be returned if err-code is ERR_UNSUPPORTED_FRESHNESS_MECHANISMS. supported-suit-cose-profiles The supported-suit-cose-profiles parameter lists the SUIT profiles supported by the TEEP Agent. Details about the cipher suite encoding can be found in Section 8.2. This otherwise optional parameter MUST be returned if err-code is ERR_UNSUPPORTED_SUIT_REPORT. challenge The challenge field is an optional parameter used for ensuring the freshness of attestation Evidence included with a QueryRequest message. When a challenge is provided in the Error message and Evidence in the form of an EAT is returned with a QueryRequest Tschofenig, et al. Expires 5 August 2026 [Page 29] Internet-Draft TEEP Protocol February 2026 message then the challenge contained in the Error message MUST be used to generate the EAT, by copying the challenge value into the eat_nonce claim, as described in the EAT profile Section 5, if the nonce-based freshness mechanism is used. For more details see Section 9. If any format other than EAT is used, it is up to that format to define the use of the challenge field. versions The versions parameter enumerates the TEEP protocol version(s) supported by the TEEP Agent. This otherwise optional parameter MUST be returned if err-code is ERR_UNSUPPORTED_MSG_VERSION. suit-reports If present, the suit-reports parameter contains a set of SUIT Reports as defined in Section 4 of [I-D.ietf-suit-report], encoded as CBOR byte strings containing either protected or unprotected SUIT Report payloads. When a SUIT Report includes its own COSE protection (signatures or MACs), the cryptographic key used MUST be distinct from the key used for the TEEP message's COSE security wrapper. If a token parameter was present in the Update message the Error message is in response to, the suit-report-nonce field MUST be present in the SUIT Report with a value matching the token parameter in the Update message. err-code The err-code parameter contains one of the error codes listed below. Only selected values are applicable to each message. Note that error codes are restricted to the range (0..23) to permit encoding as single-byte CBOR unsigned integers. Error code values 0, 11-16, and 18-22 are currently unassigned and reserved for future use. Error code 0 is intentionally reserved to prevent accidental use. Extensions that define new error codes SHOULD constrain values to this range; however, implementations that receive unrecognized error code values greater than 23 SHOULD handle them gracefully, treating them as unknown errors. This specification defines the following initial error messages: ERR_PERMANENT_ERROR (1) The received TEEP message contained incorrect fields or fields that are inconsistent with other fields. For diagnosis purposes it is RECOMMENDED to identify the failure reason in the error message field. A TEEP implementation receiving this error might refuse to communicate further with the problematic TEEP message sender, by silently dropping any TEEP messages received, for some period of time until it has reason to believe it is worth trying Tschofenig, et al. Expires 5 August 2026 [Page 30] Internet-Draft TEEP Protocol February 2026 again, but it should take care not to give up on communication. In contrast, ERR_TEMPORARY_ERROR is an indication that a more aggressive retry is warranted. ERR_UNSUPPORTED_EXTENSION (2) The TEEP implementation does not support an extension included in the TEEP message it received. For diagnosis purposes it is RECOMMENDED to identify the unsupported extension in the error message field. A TAM implementation receiving this error might retry sending the last message it sent to the sender of this error, without using any TEEP extensions. ERR_UNSUPPORTED_FRESHNESS_MECHANISMS (3) The TEEP Agent does not support any freshness algorithm mechanisms in the request message. A TAM receiving this error might retry the request using a different set of supported freshness mechanisms in the request message. ERR_UNSUPPORTED_MSG_VERSION (4) The TEEP implementation does not support the TEEP protocol version indicated in the received message. A TAM receiving this error might retry the request using a different TEEP protocol version. ERR_UNSUPPORTED_CIPHER_SUITES (5) The TEEP Agent does not support any cipher suites indicated in the request message. A TAM receiving this error might retry the request using a different set of supported cipher suites in the request message. ERR_BAD_CERTIFICATE (6) Processing of a certificate failed. For diagnosis purposes it is RECOMMENDED to include information about the failing certificate in the error message field. For example, the certificate was of an unsupported type, or the certificate was revoked by its signer. A TEEP implementation receiving this error might attempt to use an alternate certificate. ERR_ATTESTATION_REQUIRED (7) Indicates that the TEEP implementation sending this error requires attestation of the TEEP implementation receiving this error. ERR_UNSUPPORTED_SUIT_REPORT (8) Indicates that the TEEP Agent does not support the suit-cose- profile of the SUIT Reports which was sent by the TAM. The TEEP Agent must report the error code ERR_UNSUPPORTED_SUIT_REPORT supplying the supported-suit-cose-profiles. ERR_CERTIFICATE_EXPIRED (9) Tschofenig, et al. Expires 5 August 2026 [Page 31] Internet-Draft TEEP Protocol February 2026 A certificate has expired or is not currently valid. A TEEP implementation receiving this error might attempt to renew its certificate before using it again. ERR_TEMPORARY_ERROR (10) A miscellaneous temporary error, such as a memory allocation failure, occurred while processing the TEEP message. A TEEP implementation receiving this error might retry the last message it sent to the sender of this error at some later point, which is up to the implementation. ERR_MANIFEST_PROCESSING_FAILED (17) The TEEP Agent encountered one or more manifest processing failures. If the suit-reports parameter is present, it contains the failure details. A TAM receiving this error might still attempt to install or update other components that do not depend on the failed manifest. New error codes should be added sparingly, not for every implementation error. That is the intent of the err-msg field, which can be used to provide details meaningful to humans. New error codes should only be added if the TAM is expected to do something behaviorally different upon receipt of the error message, rather than just logging the event. Hence, each error code is responsible for saying what the behavioral difference is expected to be. 5. EAT Profile The TEEP protocol operates between a TEEP Agent and a TAM. While the TEEP protocol does not require use of EAT, use of EAT is encouraged and Section 4.3 explicitly defines a way to carry an Entity Attestation Token in a QueryResponse. As noted in Section 4.3.1, Evidence is opaque to the TAM, while Attestation Results are processed by the TAM in its role as the Relying Party. Although Attestation Results required by a TAM are logically separate from the TEEP protocol, this section defines requirements for building a compliant TAM that uses EATs for Attestation Results. Section 6 of [RFC9711] defines the requirement for Entity Attestation Token profiles. This section defines an EAT profile for use with TEEP. * profile-label: The profile-label for this specification is the URI . (RFC-editor: upon RFC publication, replace XXXX with the RFC number of this document.) Tschofenig, et al. Expires 5 August 2026 [Page 32] Internet-Draft TEEP Protocol February 2026 * Use of JSON, CBOR, or both: CBOR only. * CBOR Map and Array Encoding: Only definite length arrays and maps. * CBOR String Encoding: Only definite-length strings are allowed. * CBOR Preferred Serialization: Encoders must use preferred serialization, and decoders need not accept non-preferred serialization. * CBOR Tags: CBOR Tags are not used. * COSE/JOSE Protection: See Section 8.2. * COSE/JOSE Algorithms: See Section 8.2. * Detached EAT Bundle Support: DEB use is permitted. * Key Identification: COSE Key ID (kid) is used, where the key ID is the hash of a public key (where the public key may be used as a raw public key, or in a certificate) as specified in [RFC9679]. See Section 7.1.1.1 and Section 7.2.1.1 for discussion on the choice of hash algorithm. * Endorsement Identification: Optional, but semantics are the same as in Verification Key Identification. * Freshness: See Section 9 for details. When the eat_nonce claim is used, the value is a single bstr. * Claims Requirements: - The following claims are required: ueid, oemid, hwmodel, hwversion, manifests, and cnf. See Section 4.3.1 for discussion. Other claims are optional. - See Section 9 for discussion affecting whether the eat_nonce claim is used. - The sw-name claim for a Trusted Component holds the URI of the SUIT manifest for that component. - The manifests claim uses a SUIT manifest, where the manifest body contains a SUIT_Reference as defined in Section 4 of [I-D.ietf-suit-report], and the content type is as defined in [I-D.ietf-suit-report]. Tschofenig, et al. Expires 5 August 2026 [Page 33] Internet-Draft TEEP Protocol February 2026 A TAM implementation might simply accept a TEEP Agent as trustworthy based on a successful Attestation Result, and if not then attempt to update the TEEP Agent and all of its dependencies. This logic is simple but it might result in updating some components that do not need to be updated. An alternate TAM implementation might use any Additional Claims to determine whether the TEEP Agent or any of its dependencies are trustworthy, and only update the specific components that are out of date. 5.1. Relationship to AR4SI [I-D.ietf-rats-ar4si] defines an EAT profile for arbitrary Relying Parties to use with Attestation Results. However the TAM as a Relying Party needs specific claims that are not required in the AR4SI profile, and so needs its own more specific profile. In some deployments, a TAM can be used as an intermediary between Verifier and a TEEP Agent acting as an Attester in the Passport model or acting as a Relying Party in the Background Check Model of [RFC9334]. This is depicted in the example in Figure 1. In such a case, both profiles need to be obtained from the Verifier: one for use by the TAM itself, and the other to pass on to the TEEP Agent. When the TAM and Verifier are combined into the same implementation, obtaining both profiles can be straightforward, but when they are on different machines, the situation is more complex, especially if Nonces are used to ensure freshness of Evidence. There are thus several such cases: 1. The protocol between the TAM and the Verifier (which is outside the scope of TEEP itself) allows requesting multiple Attestation Results from the same Evidence. In this case, the TAM can request both EAT profiles be returned. 2. The protocol between the TAM and the Verifier only allows requesting one Attestation Result format, but the Evidence freshness mechanism does not use Nonces. In this case, the TAM can send the same Evidence in two separate requests, each requesting a different EAT profile for the Attestation Results. Tschofenig, et al. Expires 5 August 2026 [Page 34] Internet-Draft TEEP Protocol February 2026 3. The protocol between the TAM and the Verifier only allows requesting one Attestation Result format, and the Evidence freshness mechanism uses Nonces. In this case, it is simpler to not have the TAM be an intermediary, since the Verifier will require a separate Nonce for each Attestation Result, but have the Attester or Relying Party contact the Verifier directly to get Attestation Results in the AR4SI profile. 6. Mapping of TEEP Message Parameters to CBOR Labels In COSE, arrays and maps use strings, negative integers, and unsigned integers as their keys. Integers are used for compactness of encoding. Since the word "key" is mainly used in its other meaning, as a cryptographic key, this specification uses the term "label" for this usage as a map key. Message parameter labels are current defined only in the range [0..23] to permit encoding as single-byte CBOR unsigned integers, providing compact message representation. Currently, labels 0, 5, and 22 are unassigned and reserved for future use. Extensions that define new message parameters SHOULD constrain label values to this range. If future standards require additional messages beyond this range, implementations SHOULD be designed to handle gracefully any unrecognized labels, treating them as unknown optional parameters without failing to process the message. This specification uses the following mapping: +================================+=======+ | Name | Label | +================================+=======+ | supported-teep-cipher-suites | 1 | +--------------------------------+-------+ | challenge | 2 | +--------------------------------+-------+ | versions | 3 | +--------------------------------+-------+ | supported-suit-cose-profiles | 4 | +--------------------------------+-------+ | selected-version | 6 | +--------------------------------+-------+ | attestation-payload | 7 | +--------------------------------+-------+ | tc-list | 8 | +--------------------------------+-------+ | ext-list | 9 | +--------------------------------+-------+ | manifest-list | 10 | Tschofenig, et al. Expires 5 August 2026 [Page 35] Internet-Draft TEEP Protocol February 2026 +--------------------------------+-------+ | msg | 11 | +--------------------------------+-------+ | err-msg | 12 | +--------------------------------+-------+ | attestation-payload-format | 13 | +--------------------------------+-------+ | requested-tc-list | 14 | +--------------------------------+-------+ | unneeded-manifest-list | 15 | +--------------------------------+-------+ | component-id | 16 | +--------------------------------+-------+ | tc-manifest-sequence-number | 17 | +--------------------------------+-------+ | have-binary | 18 | +--------------------------------+-------+ | suit-reports | 19 | +--------------------------------+-------+ | token | 20 | +--------------------------------+-------+ | supported-freshness-mechanisms | 21 | +--------------------------------+-------+ | err-lang | 22 | +--------------------------------+-------+ | err-code | 23 | +--------------------------------+-------+ Table 2 The following CDDL description is used: Tschofenig, et al. Expires 5 August 2026 [Page 36] Internet-Draft TEEP Protocol February 2026 ; labels of mapkey for teep message parameters, uint (0..23) supported-teep-cipher-suites = 1 challenge = 2 versions = 3 supported-suit-cose-profiles = 4 selected-version = 6 attestation-payload = 7 tc-list = 8 ext-list = 9 manifest-list = 10 msg = 11 err-msg = 12 attestation-payload-format = 13 requested-tc-list = 14 unneeded-manifest-list = 15 component-id = 16 tc-manifest-sequence-number = 17 have-binary = 18 suit-reports = 19 token = 20 supported-freshness-mechanisms = 21 err-lang = 22 err-code = 23 7. Behavior Specification Behavior is specified in terms of the conceptual APIs defined in Section 6.2.1 of [RFC9397]. 7.1. TAM Behavior When the ProcessConnect API is invoked, the TAM sends a QueryRequest message. When the ProcessTeepMessage API is invoked, the TAM first does validation as specified in Section 4.1.2, and drops the message if it is not valid. It may also do additional implementation specific actions such as logging the results or attempting to update the TEEP Agent to a version that does not send invalid messages. Otherwise, it proceeds as follows. If the message includes a token, it can be used to match the response to a request previously sent by the TAM. The TAM MUST expire the token value after receiving the first response from the device that has a valid signature and ignore any subsequent messages that have the same token value. The token value MUST NOT be used for other purposes, such as a TAM to identify the devices and/or a device to identify TAMs or Trusted Components. Tschofenig, et al. Expires 5 August 2026 [Page 37] Internet-Draft TEEP Protocol February 2026 A TAM implementation that sends multiple concurrent requests to a TEEP Agent needs to track outstanding requests and their associated tokens. To prevent unbounded storage of token state, a TAM MUST implement a timeout mechanism to eventually discard unanswered requests and their tokens. This timeout SHOULD be configurable, with a recommended minimum duration of several hours to account for scenarios where devices may take considerable time to process updates and resolve dependencies (as noted in Section 7.1, such processing may take hours or longer). A TAM MAY also implement a per-device maximum storage limit for outstanding requests, reusing tokens for new requests once the per-device limit is reached (after discarding the oldest outstanding request). 7.1.1. Handling a QueryResponse Message If a QueryResponse message is received, the TAM verifies the presence of any parameters required based on the data-items-requested in the QueryRequest, and also validates that the nonce in any SUIT Report matches the token sent in the QueryRequest message if a token was present. If these requirements are not met, the TAM drops the message and sends an Update message containing an appropriate err- code and err-msg. It may also do additional implementation specific actions such as logging the results. If the requirements are met, processing continues as follows. If a QueryResponse message is received that contains an attestation- payload, the TAM checks whether it contains Evidence or an Attestation Result by inspecting the attestation-payload-format parameter. The media type defined in Section 5 indicates an Attestation Result, though future extensions might also indicate other Attestation Result formats in the future. Any other unrecognized value indicates Evidence. If it contains an Attestation Result, processing continues as in Section 7.1.1.1. If the QueryResponse is instead determined to contain Evidence, the TAM passes the Evidence (via some mechanism out of scope of this document) to an attestation Verifier (see [RFC9334]) to determine whether the Agent is in a trustworthy state. Once the TAM receives an Attestation Result from the Verifier, processing continues as in Section 7.1.1.1. 7.1.1.1. Handling an Attestation Result The Attestation Result must first be validated as follows: 1. Verify that the Attestation Result was signed by a Verifier that the TAM trusts. Tschofenig, et al. Expires 5 August 2026 [Page 38] Internet-Draft TEEP Protocol February 2026 2. Verify that the Attestation Result contains a "cnf" claim (as defined in Section 3.1 of [RFC8747]) where the key ID is the hash of the TEEP Agent public key used to verify the signature on the TEEP message, and the hash is computed using the digest algorithm specified by one of the SUIT profiles supported by the TAM. See Sections 3.4 and Section 6 of [RFC8747] for more discussion. Note: The proof-of-possession functionality for the Attestation Result may not be supported by every attestation technology or may not be enabled for use in every deployment. Based on the results of attestation (if any), any SUIT Reports, and the lists of installed, requested, and unneeded Trusted Components reported in the QueryResponse, the TAM determines, in any implementation specific manner, which Trusted Components need to be installed, updated, or deleted, if any. There are typically three cases: 1. Attestation failed. This indicates that the rest of the information in the QueryResponse cannot necessarily be trusted, as the TEEP Agent may not be healthy (or at least up to date). In this case, the TAM might attempt to use TEEP to update any Trusted Components (e.g., firmware, the TEEP Agent itself, etc.) needed to get the TEEP Agent back into an up-to-date state that would allow attestation to succeed. If the TAM does not have permission to update such components (this can happen if different TAMs manage different components in the device), the TAM instead responds with an Update message containing an appropriate err-msg, and err-code set to ERR_ATTESTATION_REQUIRED. 2. Attestation succeeded (so the QueryResponse information can be accepted as valid), but the set of Trusted Components needs to be updated based on TAM policy changes or requests from the TEEP Agent. 3. Attestation succeeded, and no changes are needed. If any Trusted Components need to be installed, updated, or deleted, the TAM sends an Update message containing SUIT Manifests with command sequences to do the relevant installs, updates, or deletes. It is important to note that the TEEP Agent's Update Procedure requires resolving and installing any dependencies indicated in the manifest, which may take some time, and the resulting Success or Error message is generated only after completing the Update Procedure. Hence, depending on the freshness mechanism in use, the TAM may need to store data (e.g., a nonce) for some time. For Tschofenig, et al. Expires 5 August 2026 [Page 39] Internet-Draft TEEP Protocol February 2026 example, if a mobile device needs an unmetered connection to download a dependency, it may take hours or longer before the device has sufficient access. A different freshness mechanism, such as timestamps, might be more appropriate in such cases. If no Trusted Components need to be installed, updated, or deleted, but the QueryResponse included Evidence, the TAM MAY (e.g., based on attestation-payload-format parameters received from the TEEP Agent in the QueryResponse) still send an Update message with no SUIT Manifests, to pass the Attestation Result back to the TEEP Agent. 7.1.2. Handling a Success or Error Message If a Success or Error message is received containing one or more SUIT Reports, the TAM also validates that the nonce in any SUIT Report matches the token sent in the Update message, and drops the message if it does not match. Otherwise, the TAM handles the update in any implementation specific way, such as updating any locally cached information about the state of the TEEP Agent, or logging the results. If an Error message is received with the error code ERR_ATTESTATION_REQUIRED, it indicates that the TEEP Agent is requesting attestation of the TAM. In this case, the TAM MUST send another QueryRequest with an attestation-payload and optionally a suit-report to the TEEP Agent. If any other Error message is received, the TAM can handle it in any implementation specific way, but Section 4.6 provides recommendations for such handling. 7.2. TEEP Agent Behavior When the RequestTA API is invoked, the TEEP Agent first checks whether the requested TA is already installed. If it is already installed, the TEEP Agent passes no data back to the caller. Otherwise, if the TEEP Agent chooses to initiate the process of requesting the indicated TA, it determines (in any implementation specific way) the TAM URI based on any TAM URI provided by the RequestTA caller and any local configuration, and passes back the TAM URI to connect to. It MAY also pass back a QueryResponse message if all of the following conditions are true: * The last QueryRequest message received from that TAM contained no token or challenge, * The ProcessError API was not invoked for that TAM since the last QueryResponse message was received from it, and Tschofenig, et al. Expires 5 August 2026 [Page 40] Internet-Draft TEEP Protocol February 2026 * The public key or certificate of the TAM is cached and not expired. When the RequestPolicyCheck API is invoked, the TEEP Agent decides whether to initiate communication with any trusted TAMs (e.g., it might choose to do so for a given TAM unless it detects that it has already communicated with that TAM recently). If so, it passes back a TAM URI to connect to. If the TEEP Agent has multiple TAMs it needs to connect with, it just passes back one, with the expectation that RequestPolicyCheck API will be invoked to retrieve each one successively until there are no more and it can pass back no data at that time. Thus, once a TAM URI is returned, the TEEP Agent can remember that it has already initiated communication with that TAM. When the ProcessError API is invoked, the TEEP Agent can handle it in any implementation specific way, such as logging the error or using the information in future choices of TAM URI. When the ProcessTeepMessage API is invoked, the Agent first does validation as specified in Section 4.1.2, and if it is not valid then the Agent responds with an Error message. Otherwise, processing continues as follows based on the type of message. 7.2.1. Handling a QueryRequest Message When a QueryRequest message is received, it is processed as follows. If the TEEP Agent requires attesting the TAM and the QueryRequest message did not contain an attestation-payload, the TEEP Agent MUST send an Error Message with the error code ERR_ATTESTATION_REQUIRED supplying the supported-freshness-mechanisms and challenge if needed. Otherwise, processing continues as follows. If the TEEP Agent requires attesting the TAM and the QueryRequest message did contain an attestation-payload, the TEEP Agent checks whether it contains Evidence or an Attestation Result by inspecting the attestation-payload-format parameter. The media type defined in Section 5 indicates an Attestation Result, though future extensions might also indicate other Attestation Result formats in the future. Any other unrecognized value indicates Evidence. If it contains an Attestation Result, processing continues as in Section 7.2.1.1. If the QueryRequest is instead determined to contain Evidence, the TEEP Agent passes the Evidence (via some mechanism out of scope of this document) to an attestation Verifier (see [RFC9334]) to determine whether the TAM is in a trustworthy state. Once the TEEP Agent receives an Attestation Result from the Verifier, processing continues as in Section 7.2.1.1. Tschofenig, et al. Expires 5 August 2026 [Page 41] Internet-Draft TEEP Protocol February 2026 The TEEP Agent MAY also use (in any implementation specific way) any SUIT Reports in the QueryRequest in determining whether it trusts the TAM. If a SUIT Report uses a suit-cose-profile that the TEEP Agent does not support, then the TEEP Agent MUST send an Error Message with the error code ERR_UNSUPPORTED_SUIT_REPORT supplying the supported- suit-cose-profiles. Otherwise, processing continues as follows. Once the Attestation Result is handled, or if the TEEP Agent does not require attesting the TAM, the Agent responds with a QueryResponse message if all fields were understood, or an Error message if any error was encountered. 7.2.1.1. Handling an Attestation Result The Attestation Result must first be validated as follows: 1. Verify that the Attestation Result was signed by a Verifier that the TEEP Agent trusts. 2. Verify that the Attestation Result contains a "cnf" claim (as defined in Section 3.1 of [RFC8747]) where the key ID is the hash of the TAM public key used to verify the signature on the TEEP message, and the hash is computed using the Digest Algorithm specified by one of the SUIT profiles supported by the TEEP Agent. See Sections 3.4 and Section 6 of [RFC8747] for more discussion. 7.2.2. Handling an Update Message When an Update message is received, the Agent attempts to unlink any SUIT manifests listed in the unneeded-manifest-list field of the message, and responds with an Error message if any error was encountered. If the unneeded-manifest-list was empty, or no error was encountered processing it, the Agent attempts to update the Trusted Components specified in the SUIT manifests by following the Update Procedure specified in [I-D.ietf-suit-manifest], and responds with a Success message if all SUIT manifests were successfully installed, or an Error message if any error was encountered. It is important to note that the Update Procedure requires resolving and installing any dependencies indicated in the manifest, which may take some time, and the Success or Error message is generated only after completing the Update Procedure. 8. Cipher Suites TEEP requires algorithms for various purposes: Tschofenig, et al. Expires 5 August 2026 [Page 42] Internet-Draft TEEP Protocol February 2026 * Algorithms for signing TEEP messages exchanged between the TEEP Agent and the TAM. * Algorithms for signing EAT-based Evidence sent by the Attester via the TEEP Agent and the TAM to the Verifier. * Algorithms for encrypting EAT-based Evidence sent by the TEEP Agent to the TAM. (The TAM will decrypt the encrypted Evidence and will forward it to the Verifier.) * Algorithms for signing and optionally encrypting SUIT reports sent by the TEEP Agent to the TAM. * Algorithms for signing and optionally encrypting SUIT manifests sent by the Trusted Component Signer to the TEEP Agent. Further details are provided for the protection of TEEP messages, SUIT Reports, and EATs. 8.1. TEEP Messages The TEEP protocol uses COSE for protection of TEEP messages in both directions. To negotiate cryptographic mechanisms and algorithms, the TEEP protocol defines the following cipher suite structure, which is used to specify an ordered set of operations (e.g., sign) done as part of composing a TEEP message. Although this specification only specifies the use of signing and relies on payload encryption to protect sensitive information, future extensions might specify support for encryption and/or MAC operations if needed. Tschofenig, et al. Expires 5 August 2026 [Page 43] Internet-Draft TEEP Protocol February 2026 ; teep-cipher-suites $teep-cipher-suite /= teep-cipher-suite-sign1-ed25519 $teep-cipher-suite /= teep-cipher-suite-sign1-esp256 ;The following two cipher suites have only a single operation each. ;Other cipher suites may be defined to have multiple operations. ;It is MANDATORY for TAM to support them, and OPTIONAL ;to support any additional ones that use COSE_Sign_Tagged, or other ;signing, encryption, or MAC algorithms. teep-operation-sign1-ed25519 = [ cose-sign1, cose-alg-ed25519 ] teep-operation-sign1-esp256 = [ cose-sign1, cose-alg-esp256 ] teep-cipher-suite-sign1-ed25519 = [ teep-operation-sign1-ed25519 ] teep-cipher-suite-sign1-esp256 = [ teep-operation-sign1-esp256 ] ;MANDATORY for TAM and TEEP Agent to support the following COSE ;operations, and OPTIONAL to support additional ones such as ;COSE_Sign_Tagged, COSE_Encrypt0_Tagged, etc. cose-sign1 = 18 ; CoAP Content-Format value ;MANDATORY for TAM to support the following, and OPTIONAL to ;implement any additional algorithms from the IANA COSE Algorithms ;registry. cose-alg-esp256 = -9 ; ECDSA using P-256 curve and SHA-256 cose-alg-ed25519 = -19 ; EdDSA using Ed25519 curve Each operation in a given cipher suite has two elements: * a COSE-type defined in Section 2 of [RFC9052] that identifies the type of operation, and * a specific cryptographic algorithm as defined in the COSE Algorithms registry [COSE.Algorithm] to be used to perform that operation. A TAM MUST support both of the cipher suites defined above. A TEEP Agent MUST support at least one of the two but can choose which one. For example, a TEEP Agent might choose a given cipher suite if it has hardware support for it. A TAM or TEEP Agent MAY also support any other algorithms in the COSE Algorithms registry in addition to the mandatory ones listed above. It MAY also support use with COSE_Sign or other COSE types in additional cipher suites. Tschofenig, et al. Expires 5 August 2026 [Page 44] Internet-Draft TEEP Protocol February 2026 Any cipher suites without confidentiality protection can only be added if the associated specification includes a discussion of security considerations and applicability, since manifests may carry sensitive information. For example, Section 6 of [RFC9397] permits implementations that terminate transport security inside the TEE and if the transport security provides confidentiality then additional encryption might not be needed in the manifest for some use cases. For most use cases, however, manifest confidentiality will be needed to protect sensitive fields from the TAM as discussed in Section 9.8 of [RFC9397]. The cipher suites defined above do not do encryption at the TEEP layer, but permit encryption of the SUIT payload using a mechanism such as [I-D.ietf-suit-firmware-encryption]. See Section 10 and Section 8.2 for more discussion of specific payloads. For the initial QueryRequest message, unless the TAM has more specific knowledge about the TEEP Agent (e.g., if the QueryRequest is sent in response to some underlying transport message that contains a hint), the message does not use COSE_Sign1 with one of the above cipher suites, but instead uses COSE_Sign with multiple signatures, one for each algorithm used in any of the cipher suites listed in the supported-teep-cipher-suites parameter of the QueryRequest, so that a TEEP Agent supporting any one of them can verify a signature. If the TAM does have specific knowledge about which cipher suite the TEEP Agent supports, it MAY instead use that cipher suite with the QueryRequest. For an Error message with code ERR_UNSUPPORTED_CIPHER_SUITES, the TEEP Agent MUST protect it with any of the cipher suites mandatory for the TAM. For all other TEEP messages between the TAM and TEEP Agent, the selected TEEP cipher suite MUST be used in both directions. 8.2. EATs and SUIT Reports TEEP uses COSE for confidentiality of EATs and SUIT Reports sent by a TEEP Agent. The TEEP Agent obtains a signed EAT and then SHOULD encrypt it using the TAM as the recipient, unless the transport layer provides sufficient confidentiality protection or the TEEP Agent's deployment environment does not permit access to the TAM's public key. A SUIT Report is created by a SUIT processor, which is part of the TEEP Agent itself. The TEEP Agent is therefore in control of signing the SUIT Report and SHOULD encrypt it for the same reasons, to protect sensitive information from intermediate processors and transport mechanisms. Again, the TAM is the recipient of the encrypted content. For content-key distribution Ephemeral-Static Tschofenig, et al. Expires 5 August 2026 [Page 45] Internet-Draft TEEP Protocol February 2026 Diffie-Hellman (ES-DH) is used in this specification. See Section 8.5.5 and Appendix B of [RFC9052] for more details. (If [I-D.ietf-suit-firmware-encryption] is used, it is also the same as discussed in Section 6.2 of that document.) ES-DH is a scheme that provides public key encryption given a recipient's public key. Hence, the TEEP Agent needs to be in possession of the public key of the TAM. See Section 5 of [RFC9397] for more discussion of TAM keys used by the TEEP Agent. There are multiple variants of this scheme; this document uses the variant specified in Section 8.5.5 of [RFC9052]. The following two layer structure is used: * Layer 0: Has a content encrypted with the Content Encryption Key (CEK), a symmetric key. For encrypting SUIT Reports and EATs the content MUST NOT be detached. * Layer 1: Uses the AES Key Wrap algorithm to encrypt the randomly generated CEK with the Key Encryption Key (KEK) derived with ES- DH, whereby the resulting symmetric key is fed into the HKDF-based key derivation function. As a result, the two layers combine ES-DH with AES-KW and HKDF. This document reuses the CDDL defined in Section 6.2.3 of [I-D.ietf-suit-firmware-encryption] and the context information structure defined in Section 6.2.4 of [I-D.ietf-suit-firmware-encryption] although with an important modification. The COSE_KDF_Context.SuppPubInfo.other value MUST be set to "SUIT Report Encryption" when a SUIT Report is encrypted and MUST be set to "EAT Encryption" when an EAT is encrypted. The COSE_KDF_Context.SuppPubInfo.other field captures the protocol in which the ES-DH content key distribution algorithm is used. This specification defines cipher suites for confidentiality protection of EATs and SUIT Reports. The TAM MUST support each cipher suite defined below, based on definitions in [I-D.ietf-suit-mti]. A TEEP Agent MUST support at least one of the cipher suites below but can choose which one. For example, a TEEP Agent might choose a given cipher suite if it has hardware support for it. A TAM or TEEP Agent MAY also support other algorithms in the COSE Algorithms registry. It MAY also support use with COSE_Encrypt or other COSE types in additional cipher suites. Tschofenig, et al. Expires 5 August 2026 [Page 46] Internet-Draft TEEP Protocol February 2026 ; suit-cose-profile $suit-cose-profile /= suit-sha256-esp256-ecdh-a128ctr $suit-cose-profile /= suit-sha256-ed25519-ecdh-a128ctr $suit-cose-profile /= suit-sha256-esp256-ecdh-a128gcm $suit-cose-profile /= suit-sha256-ed25519-ecdh-chacha-poly 9. Attestation Freshness Mechanisms A freshness mechanism determines how a TAM can tell whether an attestation payload provided in a QueryResponse is fresh. There are multiple ways this can be done as discussed in Section 10 of [RFC9334]. Each freshness mechanism is identified with an integer value, which corresponds to an IANA registered freshness mechanism (see the IANA Considerations section of [I-D.ietf-rats-reference-interaction-models]). This document uses the following freshness mechanisms which may be added to in the future by TEEP extensions: ; freshness-mechanisms FRESHNESS_NONCE = 0 FRESHNESS_TIMESTAMP = 1 $freshness-mechanism /= FRESHNESS_NONCE $freshness-mechanism /= FRESHNESS_TIMESTAMP An implementation MUST support the Nonce mechanism and MAY support additional mechanisms. In the Nonce mechanism, the attestation payload MUST include a nonce provided in the QueryRequest challenge if the Background Check model is used, or in the QueryRequest token if the Passport model is used. The timestamp mechanism uses a timestamp determined via mechanisms outside the TEEP protocol, and the challenge is only needed in the QueryRequest message if a challenge is needed in generating the attestation payload for reasons other than freshness. If a TAM supports multiple freshness mechanisms that require different challenge formats, the QueryRequest message can currently only send one such challenge. This situation is expected to be rare, but should it occur, the TAM can choose to prioritize one of them and exclude the other from the supported-freshness-mechanisms in the QueryRequest, and resend the QueryRequest with the other mechanism if an ERR_UNSUPPORTED_FRESHNESS_MECHANISMS Error is received that indicates the TEEP Agent supports the other mechanism. Tschofenig, et al. Expires 5 August 2026 [Page 47] Internet-Draft TEEP Protocol February 2026 10. Security Considerations This section summarizes the security considerations discussed in this specification: Cryptographic Algorithms TEEP protocol messages exchanged between the TAM and the TEEP Agent are protected using COSE. This specification relies on the cryptographic algorithms provided by COSE. Public key based authentication is used by the TEEP Agent to authenticate the TAM and vice versa. Attestation A TAM relies on signed Attestation Results provided by a Verifier, either obtained directly using a mechanism outside the TEEP protocol (by using some mechanism to pass Evidence obtained in the attestation payload of a QueryResponse, and getting back the Attestation Results), or indirectly via the TEEP Agent forwarding the Attestation Results in the attestation payload of a QueryResponse. See the security considerations of the specific mechanism in use (e.g., EAT) for more discussion. An impersonation attack, where one TEEP Agent attempts to use the attestation payload of another TEEP Agent, can be prevented using a proof-of-possession approach. The "cnf" claim is mandatory in the EAT profile for EAT for this purpose. See Section 6 of [RFC8747] and Section 7.1.1.1 and Section 7.2.1.1 of this document for more discussion. Trusted Component Binaries Each Trusted Component binary is signed by a Trusted Component Signer. It is the responsibility of the TAM to relay only verified Trusted Components from authorized Trusted Component Signers. Delivery of a Trusted Component to the TEEP Agent is then the responsibility of the TAM, using the security mechanisms provided by the TEEP protocol. To protect the Trusted Component binary, the SUIT manifest format is used and it offers a variety of security features, including digital signatures and content encryption, if a SUIT mechanism such as [I-D.ietf-suit-firmware-encryption] is used. Personalization Data A Trusted Component Signer or TAM can supply personalization data along with a Trusted Component. This data is also protected by a SUIT manifest. Personalization data is signed and encrypted by a Trusted Component Signer, if a SUIT mechanism such as [I-D.ietf-suit-firmware-encryption] is used. Tschofenig, et al. Expires 5 August 2026 [Page 48] Internet-Draft TEEP Protocol February 2026 TEEP Broker As discussed in Section 6 of [RFC9397], the TEEP protocol typically relies on a TEEP Broker to relay messages between the TAM and the TEEP Agent. When the TEEP Broker is compromised, it can drop messages, delay the delivery of messages, and replay messages, but it cannot modify those messages. (A replay would be, however, detected by the TEEP Agent.) A compromised TEEP Broker could reorder messages in an attempt to install an old version of a Trusted Component. Information in the manifest ensures that TEEP Agents are protected against such downgrade attacks based on features offered by the manifest itself. Replay Protection The TEEP protocol supports replay protection as follows. The transport protocol under the TEEP protocol might provide replay protection, but may be terminated in the TEEP Broker which is not trusted by the TEEP Agent and so the TEEP protocol does replay protection itself. If attestation of the TAM is used, the attestation freshness mechanism provides replay protection for attested QueryRequest messages. If non-attested QueryRequest messages are replayed, the TEEP Agent will generate QueryResponse or Error messages, but the REE can already conduct Denial of Service attacks against the TEE and/or the TAM even without the TEEP protocol. QueryResponse messages have replay protection via attestation freshness mechanism, or the token field in the message if attestation is not used. Update messages have replay protection via the suit-manifest-sequence-number (see Section 8.4.2 of [I-D.ietf-suit-manifest]). Error and Success messages have replay protection via SUIT Reports and/or the token field in the message, where a TAM can detect which message it is in response to. Trusted Component Signer Compromise A TAM is responsible for vetting Trusted Components before distributing them to TEEP Agents. It is RECOMMENDED to provide a way to update the trust anchor store used by the TEE, for example using a firmware update mechanism such as [I-D.ietf-rats-concise-ta-stores]. Thus, if a Trusted Component Signer is later compromised, the TAM can update the trust anchor store used by the TEE, for example using a firmware update mechanism. CA Compromise The CA issuing certificates to a TEE or a Trusted Component Signer might get compromised. It is RECOMMENDED to provide a way to update the trust anchor store used by the TEE, for example by using a firmware update mechanism, Concise TA Stores [I-D.ietf-rats-concise-ta-stores], Trust Anchor Management Tschofenig, et al. Expires 5 August 2026 [Page 49] Internet-Draft TEEP Protocol February 2026 Protocol (TAMP) [RFC5934] or a similar mechanism. If the CA issuing certificates to devices gets compromised then these devices will be rejected by a TAM, if revocation is available to the TAM. TAM Certificate Expiry The integrity and the accuracy of the clock within the TEE determines the ability to determine an expired TAM certificate, if certificates are used. Compromised Time Source As discussed above, certificate validity checks rely on comparing validity dates to the current time, which relies on having a trusted source of time, such as [RFC8915]. A compromised time source could thus be used to subvert such validity checks. 10.1. Operational Considerations This section summarizes operational and management guidance for deployments using the TEEP protocol. It complements the general operational guidelines in the IETF operations-area document [I-D.ietf-opsawg-rfc5706bis] and refers implementers to the architecture and conceptual APIs in [RFC9397] for configuration and management points. * Configuration and placement: Protocol-specific configuration is typically performed in the TAM, the TEEP Agent, and any Verifier used by the TAM. See the conceptual APIs in [RFC9397] for the configuration points exposed by implementations (e.g., which Trusted Components to manage, trust anchors, and per-device state). * Token lifecycle and state management: Tokens are used to match requests and responses and to provide limited replay protection. The guidance in this document requires random initial tokens and non-reuse; implementers MUST ensure bounded storage of outstanding tokens (timeouts, per-device caps) and MUST expire tokens after the first valid response. Operational deployments SHOULD tune token timeouts to accommodate device processing time (see Section 7.1). * Key and certificate lifecycle: Operators MUST run procedures for certificate and key issuance, rollover, revocation, and timely renewal. Implementations SHOULD support certificate status checks and have clear behavior when certificates are expired or revoked (see err-code behaviors such as ERR_CERTIFICATE_EXPIRED and ERR_BAD_CERTIFICATE). Tschofenig, et al. Expires 5 August 2026 [Page 50] Internet-Draft TEEP Protocol February 2026 * Logging, monitoring, and diagnostics: Implementations SHOULD log operational events, but MUST avoid placing sensitive data (e.g., raw Evidence, private keys) into logs. Diagnostic fields, such as err-msg (optionally accompanied by err-lang), are intended for human operators; logs should capture structured error codes and minimal diagnostic text to aid incident response. * Rate limiting and DoS protection: Implementations SHOULD apply rate limits and backoff policies to mitigate malformed or high- volume requests. Agents SHOULD limit the size and number of concurrent manifests processed and protect local resources (CPU, memory, storage) from exhausting. * Time synchronization: Accurate device time is important for certificate validity checks and for some attestation freshness mechanisms. Operators SHOULD ensure devices maintain adequate time synchronization. * Privacy and data minimization Attestation results, SUIT reports, and system-property-claims can contain identifying information. Do not expose such data to unauthorised parties; apply least- privilege principles when requesting or returning attestation or component lists. * Upgrade and rollback procedures: Manifest processing can be disruptive. Operators SHOULD plan for safe upgrade and rollback procedures, including verification of manifests prior to execution, mechanisms for retry, and consideration of partial failure modes. * Transport and deployment-specific concerns: TEEP is transport agnostic; operators MUST ensure the chosen transport provides adequate confidentiality, integrity, authentication, and replay protection. See the HTTP binding draft [I-D.ietf-teep-otrp-over-http] for transport-specific operational details when that binding is used. * Scaling and batching: Large-scale deployments SHOULD consider batching updates and asynchronous workflows to avoid overwhelming devices or management servers. Unsolicited messages and polling behavior should be chosen to balance timeliness and operational load. * Emergency recovery: Provide procedures for emergency recovery, including factory-reset processes, certificate revocation handling, and operational steps for devices that become non- responsive after updates. Tschofenig, et al. Expires 5 August 2026 [Page 51] Internet-Draft TEEP Protocol February 2026 Where operational considerations are covered by other documents (for example, the TEEP architecture [RFC9397]), implementers SHOULD follow the guidance in those documents as applicable. 11. Transport Considerations This specification defines the TEEP protocol as a set of messages to be exchanged between a TAM and a TEEP Agent. However, this specification is transport-agnostic and does not mandate use of a specific transport protocol. The TEEP protocol messages are signed and can be optionally encrypted at the protocol layer, providing end- to-end security independent of the underlying transport. Companion specifications define how TEEP messages are transported over specific protocols. For example, [I-D.ietf-teep-otrp-over-http] defines how TEEP messages are transported over HTTP/HTTPS. TEEP transport specifications MUST provide the following information: * Whether the transport provides reliability guarantees and ordered delivery * How message loss and retransmission are handled * Recovery mechanisms for mid-transaction transport failures * How the transport handles duplicate messages and idempotency * How transport-layer errors are reported to the TEEP Agent and TAM Implementations SHOULD use a transport that provides authentication of the remote endpoint and confidentiality protection of messages in flight, or provide these protections at the TEEP protocol layer. As discussed in [RFC9397], the TEEP protocol uses end-to-end cryptographic protection via COSE to ensure that messages cannot be modified by intermediaries, such as the TEEP Broker. The token field in TEEP messages (present in QueryRequest and Update messages) is used for request-response matching. As described in Section 7.1, the token MUST be unique among outstanding requests for a given device at a given TAM, but tokens MAY be reused for new requests once the previous request has received a response or timed out. Token reuse across multiple devices or TAMs is permitted but not required; implementations MAY choose to make tokens globally unique for audit or logging purposes. Tschofenig, et al. Expires 5 August 2026 [Page 52] Internet-Draft TEEP Protocol February 2026 12. Privacy Considerations Depending on the properties of the attestation mechanism, it is possible to uniquely identify a device based on information in the attestation payload or in the certificate used to sign the attestation payload. This uniqueness may raise privacy concerns. To lower the privacy implications, the TEEP Agent MUST present its attestation payload only to an authenticated and authorized TAM and, when using an EAT, it SHOULD use encryption as discussed in [RFC9711] unless the transport layer provides sufficient confidentiality protection. Encryption is particularly important since confidentiality is not provided by the TEEP protocol itself and the transport protocol under the TEEP protocol might be implemented outside of any TEE. If any mechanism other than EAT is used, that mechanism MUST specify how privacy is provided. Since SUIT Reports can also contain sensitive information, a TEEP Agent SHOULD also encrypt SUIT Reports as discussed in Section 8.2, particularly when they contain device identifiers or other sensitive operational data. In addition, in the usage scenario discussed in Section 4.4.1, a device reveals its IP address to the Trusted Component Binary server. This can reveal to that server at least a clue as to its location, which might be sensitive information in some cases. EATs and SUIT Reports from a TAM can also be present in a QueryRequest. Typically, the ability to uniquely identify a TAM is less of a concern than it is for TEEP Agents, but where confidentiality is a concern for the TAM, such EATs and SUIT Reports SHOULD be encrypted just like ones from TEEP Agents. 13. IANA Considerations 13.1. Media Type Registration IANA is requested to assign a media type for application/teep+cbor. Type name: application Subtype name: teep+cbor Required parameters: none Optional parameters: none Encoding considerations: Same as encoding considerations of application/cbor. Tschofenig, et al. Expires 5 August 2026 [Page 53] Internet-Draft TEEP Protocol February 2026 Security considerations: See Security Considerations Section of this document. Interoperability considerations: Same as interoperability considerations of application/cbor as specified in [RFC8949]. Published specification: This document. Applications that use this media type: TEEP protocol implementations Fragment identifier considerations: N/A Additional information: * Deprecated alias names for this type: N/A * Magic number(s): N/A * File extension(s): N/A * Macintosh file type code(s): N/A Person to contact for further information: teep@ietf.org Intended usage: COMMON Restrictions on usage: none Author: See the "Authors' Addresses" section of this document Change controller: IETF 13.2. TEEP Message Type Registry IANA is requested to create a new registry titled "TEEP Message Types" within the TEEP registry. The registry has the following format: Tschofenig, et al. Expires 5 August 2026 [Page 54] Internet-Draft TEEP Protocol February 2026 +=======+===========================+===============+ | Value | Name | Reference | +=======+===========================+===============+ | 0 | (Reserved) | This document | +-------+---------------------------+---------------+ | 1 | TEEP-TYPE-query-request | This document | +-------+---------------------------+---------------+ | 2 | TEEP-TYPE-query-response | This document | +-------+---------------------------+---------------+ | 3 | TEEP-TYPE-update | This document | +-------+---------------------------+---------------+ | 4 | (Reserved) | This document | +-------+---------------------------+---------------+ | 5 | TEEP-TYPE-teep-success | This document | +-------+---------------------------+---------------+ | 6 | TEEP-TYPE-teep-error | This document | +-------+---------------------------+---------------+ | 7-23 | (Reserved for future use) | This document | +-------+---------------------------+---------------+ Table 3 Registration procedures are as follows: * 0-12: Standards Action * 13-23: Specification Required 13.3. data-item-requested Bitmap Registry IANA is requested to create a registry titled "TEEP data-item- requested Bits" within the TEEP registry. The registry has the following format: Tschofenig, et al. Expires 5 August 2026 [Page 55] Internet-Draft TEEP Protocol February 2026 +======+====================+=======================+===========+ | Bit | Name | Description | Reference | +======+====================+=======================+===========+ | 0 | attestation | TAM requests | This | | | | attestation payload | document | +------+--------------------+-----------------------+-----------+ | 1 | trusted-components | TAM queries installed | This | | | | Trusted Components | document | +------+--------------------+-----------------------+-----------+ | 2 | extensions | TAM queries supported | This | | | | extensions | document | +------+--------------------+-----------------------+-----------+ | 3 | suit-reports | TAM requests SUIT | This | | | | Reports | document | +------+--------------------+-----------------------+-----------+ | 4-31 | (Reserved for | | This | | | future use) | | document | +------+--------------------+-----------------------+-----------+ Table 4 Registration procedures are as follows: * 0-23: Standards Action * 24-31: Specification Required 13.4. TEEP Error Code Registry IANA is requested to create a registry titled "TEEP Error Codes" within the TEEP registry. The registry has the following format: +=====+====================================+==============+=========+ |Value|Name | Description |Reference| +=====+====================================+==============+=========+ |0 |(Reserved) | Reserved to |This | | | | prevent |document | | | | accidental | | | | | use | | +-----+------------------------------------+--------------+---------+ |1 |ERR_PERMANENT_ERROR | Incorrect or |This | | | | inconsistent |document | | | | fields | | +-----+------------------------------------+--------------+---------+ |2 |ERR_UNSUPPORTED_EXTENSION | Unsupported |This | | | | extension in |document | | | | message | | +-----+------------------------------------+--------------+---------+ Tschofenig, et al. Expires 5 August 2026 [Page 56] Internet-Draft TEEP Protocol February 2026 |3 |ERR_UNSUPPORTED_FRESHNESS_MECHANISMS| Unsupported |This | | | | freshness |document | | | | mechanism | | +-----+------------------------------------+--------------+---------+ |4 |ERR_UNSUPPORTED_MSG_VERSION | Unsupported |This | | | | TEEP |document | | | | protocol | | | | | version | | +-----+------------------------------------+--------------+---------+ |5 |ERR_UNSUPPORTED_CIPHER_SUITES | Unsupported |This | | | | cipher |document | | | | suites | | +-----+------------------------------------+--------------+---------+ |6 |ERR_BAD_CERTIFICATE | Certificate |This | | | | processing |document | | | | failed | | +-----+------------------------------------+--------------+---------+ |7 |ERR_ATTESTATION_REQUIRED | Attestation |This | | | | is required |document | +-----+------------------------------------+--------------+---------+ |8 |ERR_UNSUPPORTED_SUIT_REPORT | Unsupported |This | | | | SUIT Report |document | | | | profile | | +-----+------------------------------------+--------------+---------+ |9 |ERR_CERTIFICATE_EXPIRED | Certificate |This | | | | has expired |document | | | | or is | | | | | invalid | | +-----+------------------------------------+--------------+---------+ |10 |ERR_TEMPORARY_ERROR | Temporary |This | | | | error (e.g., |document | | | | memory | | | | | allocation) | | +-----+------------------------------------+--------------+---------+ |11-16|(Reserved for future use) | | | +-----+------------------------------------+--------------+---------+ |17 |ERR_MANIFEST_PROCESSING_FAILED | Manifest |This | | | | processing |document | | | | failure | | +-----+------------------------------------+--------------+---------+ |18-22|(Reserved for future use) | | | +-----+------------------------------------+--------------+---------+ |23 |(Reserved) | Reserved for | | | | | future use | | +-----+------------------------------------+--------------+---------+ Table 5 Tschofenig, et al. Expires 5 August 2026 [Page 57] Internet-Draft TEEP Protocol February 2026 Note: Error codes are constrained to the range 0-23 to permit encoding as single-byte CBOR unsigned integers. Registration procedures are as follows: * 1-10, 17: Standards Action * 11-16, 18-23: Reserved for future use by Specification Required 13.5. TEEP CBOR Label Registry IANA is requested to create a registry titled "TEEP CBOR Labels" within the TEEP registry. The registry has the following format: +=======+=================+===========================+===========+ | Label | Name | Type | Reference | +=======+=================+===========================+===========+ | 0 | (Reserved) | | | +-------+-----------------+---------------------------+-----------+ | 1 | supported-teep- | array | This | | | cipher-suites | | document | +-------+-----------------+---------------------------+-----------+ | 2 | challenge | bstr | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 3 | versions | array | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 4 | supported-suit- | array | This | | | cose-profiles | | document | +-------+-----------------+---------------------------+-----------+ | 5 | (Reserved) | | | +-------+-----------------+---------------------------+-----------+ | 6 | selected- | uint | This | | | version | | document | +-------+-----------------+---------------------------+-----------+ | 7 | attestation- | bstr | This | | | payload | | document | +-------+-----------------+---------------------------+-----------+ | 8 | tc-list | array | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 9 | ext-list | array | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 10 | manifest-list | array | This | | | | | document | +-------+-----------------+---------------------------+-----------+ Tschofenig, et al. Expires 5 August 2026 [Page 58] Internet-Draft TEEP Protocol February 2026 | 11 | msg | text | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 12 | err-msg | text | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 13 | attestation- | text | This | | | payload-format | | document | +-------+-----------------+---------------------------+-----------+ | 14 | requested-tc- | array | This | | | list | | document | +-------+-----------------+---------------------------+-----------+ | 15 | unneeded- | array | This | | | manifest-list | | document | +-------+-----------------+---------------------------+-----------+ | 16 | component-id | SUIT_Component_Identifier | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 17 | tc-manifest- | uint | This | | | sequence-number | | document | +-------+-----------------+---------------------------+-----------+ | 18 | have-binary | bool | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 19 | suit-reports | array | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 20 | token | bstr | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 21 | supported- | array | This | | | freshness- | | document | | | mechanisms | | | +-------+-----------------+---------------------------+-----------+ | 22 | (Reserved) | | | +-------+-----------------+---------------------------+-----------+ | 23 | err-code | uint | This | | | | | document | +-------+-----------------+---------------------------+-----------+ | 2-255 | (Reserved for | | | | | future use) | | | +-------+-----------------+---------------------------+-----------+ | 256- | (Reserved for | | | | | future use) | | | +-------+-----------------+---------------------------+-----------+ Table 6 Tschofenig, et al. Expires 5 August 2026 [Page 59] Internet-Draft TEEP Protocol February 2026 Note: Labels are not constrained to a specific range. Registration procedures are as follows: * 0-255:: Standards Action * 256 and above: Specification Required 13.6. TEEP Cipher Suite Registry IANA is requested to create a registry titled "TEEP Cipher Suites" within the TEEP registry. The registry has the following format: +=======+=================================+===============+ | Value | Name | Reference | +=======+=================================+===============+ | 0 | teep-cipher-suite-sign1-ed25519 | This document | +-------+---------------------------------+---------------+ | 1 | teep-cipher-suite-sign1-esp256 | This document | +-------+---------------------------------+---------------+ | 2-255 | (Reserved for future use) | | +-------+---------------------------------+---------------+ Table 7 Registration procedures are as follows: * 0-23: Standards Action * 24-255: Specification Required Any new cipher suites MUST provide authentication, integrity, and SHOULD provide confidentiality protection. 13.7. TEEP Freshness Mechanism Registry IANA is requested to create a registry titled "TEEP Freshness Mechanisms" within the TEEP registry. The registry has the following format: Tschofenig, et al. Expires 5 August 2026 [Page 60] Internet-Draft TEEP Protocol February 2026 +=======+===========================+===============+ | Value | Name | Reference | +=======+===========================+===============+ | 0 | FRESHNESS_NONCE | This document | +-------+---------------------------+---------------+ | 1 | FRESHNESS_TIMESTAMP | This document | +-------+---------------------------+---------------+ | 2-255 | (Reserved for future use) | | +-------+---------------------------+---------------+ Table 8 Registration procedures are as follows: * 0-23: Standards Action * 24-255: Specification Required 14. References 14.1. Normative References [COSE.Algorithm] IANA, "COSE Algorithms", n.d., . [I-D.ietf-suit-manifest] Moran, B., Tschofenig, H., Birkholz, H., Zandberg, K., and O. Rønningstad, "A Concise Binary Object Representation (CBOR)-based Serialization Format for the Software Updates for Internet of Things (SUIT) Manifest", Work in Progress, Internet-Draft, draft-ietf-suit-manifest-34, 28 May 2025, . [I-D.ietf-suit-mti] Moran, B., Rønningstad, O., and A. Tsukamoto, "Cryptographic Algorithms for Internet of Things (IoT) Devices", Work in Progress, Internet-Draft, draft-ietf- suit-mti-23, 22 July 2025, . Tschofenig, et al. Expires 5 August 2026 [Page 61] Internet-Draft TEEP Protocol February 2026 [I-D.ietf-suit-report] Moran, B. and H. Birkholz, "Secure Reporting of SUIT Update Status", Work in Progress, Internet-Draft, draft- ietf-suit-report-18, 9 December 2025, . [I-D.ietf-suit-trust-domains] Moran, B. and K. Takayama, "Software Update for the Internet of Things (SUIT) Manifest Extensions for Multiple Trust Domain", Work in Progress, Internet-Draft, draft- ietf-suit-trust-domains-12, 22 July 2025, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 2003, . [RFC5198] Klensin, J. and M. Padlipsky, "Unicode Format for Network Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008, . [RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, September 2009, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8747] Jones, M., Seitz, L., Selander, G., Erdtman, S., and H. Tschofenig, "Proof-of-Possession Key Semantics for CBOR Web Tokens (CWTs)", RFC 8747, DOI 10.17487/RFC8747, March 2020, . [RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", STD 94, RFC 8949, DOI 10.17487/RFC8949, December 2020, . Tschofenig, et al. Expires 5 August 2026 [Page 62] Internet-Draft TEEP Protocol February 2026 [RFC9052] Schaad, J., "CBOR Object Signing and Encryption (COSE): Structures and Process", STD 96, RFC 9052, DOI 10.17487/RFC9052, August 2022, . [RFC9679] Isobe, K., Tschofenig, H., and O. Steele, "CBOR Object Signing and Encryption (COSE) Key Thumbprint", RFC 9679, DOI 10.17487/RFC9679, December 2024, . [RFC9711] Lundblade, L., Mandyam, G., O'Donoghue, J., and C. Wallace, "The Entity Attestation Token (EAT)", RFC 9711, DOI 10.17487/RFC9711, April 2025, . 14.2. Informative References [I-D.ietf-opsawg-rfc5706bis] Claise, B., Clarke, J., Farrel, A., Barguil, S., Pignataro, C., and R. Chen, "Guidelines for Considering Operations and Management in IETF Specifications", Work in Progress, Internet-Draft, draft-ietf-opsawg-rfc5706bis-01, 17 December 2025, . [I-D.ietf-rats-ar4si] Voit, E., Birkholz, H., Hardjono, T., Fossati, T., and V. Scarlata, "Attestation Results for Secure Interactions", Work in Progress, Internet-Draft, draft-ietf-rats-ar4si- 09, 15 August 2025, . [I-D.ietf-rats-concise-ta-stores] Wallace, C., Housley, R., Fossati, T., and Y. Deshpande, "Concise TA Stores (CoTS)", Work in Progress, Internet- Draft, draft-ietf-rats-concise-ta-stores-02, 5 December 2023, . [I-D.ietf-rats-reference-interaction-models] Birkholz, H., Eckel, M., Pan, W., and E. Voit, "Reference Interaction Models for Remote Attestation Procedures", Work in Progress, Internet-Draft, draft-ietf-rats- reference-interaction-models-15, 5 November 2025, . Tschofenig, et al. Expires 5 August 2026 [Page 63] Internet-Draft TEEP Protocol February 2026 [I-D.ietf-suit-firmware-encryption] Tschofenig, H., Housley, R., Moran, B., Brown, D., and K. Takayama, "Encrypted Payloads in SUIT Manifests", Work in Progress, Internet-Draft, draft-ietf-suit-firmware- encryption-26, 8 December 2025, . [I-D.ietf-teep-otrp-over-http] Thaler, D., "HTTP Transport for Trusted Execution Environment Provisioning: Agent Initiated Communication", Work in Progress, Internet-Draft, draft-ietf-teep-otrp- over-http-15, 27 March 2023, . [RFC5934] Housley, R., Ashmore, S., and C. Wallace, "Trust Anchor Management Protocol (TAMP)", RFC 5934, DOI 10.17487/RFC5934, August 2010, . [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, . [RFC8915] Franke, D., Sibold, D., Teichel, K., Dansarie, M., and R. Sundblad, "Network Time Security for the Network Time Protocol", RFC 8915, DOI 10.17487/RFC8915, September 2020, . [RFC9124] Moran, B., Tschofenig, H., and H. Birkholz, "A Manifest Information Model for Firmware Updates in Internet of Things (IoT) Devices", RFC 9124, DOI 10.17487/RFC9124, January 2022, . [RFC9334] Birkholz, H., Thaler, D., Richardson, M., Smith, N., and W. Pan, "Remote ATtestation procedureS (RATS) Architecture", RFC 9334, DOI 10.17487/RFC9334, January 2023, . [RFC9397] Pei, M., Tschofenig, H., Thaler, D., and D. Wheeler, "Trusted Execution Environment Provisioning (TEEP) Architecture", RFC 9397, DOI 10.17487/RFC9397, July 2023, . Tschofenig, et al. Expires 5 August 2026 [Page 64] Internet-Draft TEEP Protocol February 2026 [RFC9782] Lundblade, L., Birkholz, H., and T. Fossati, "Entity Attestation Token (EAT) Media Types", RFC 9782, DOI 10.17487/RFC9782, May 2025, . A. Contributors We would like to thank Brian Witten (Symantec), Tyler Kim (Solacia), Nick Cook (Arm), and Minho Yoo (IoTrust) for their contributions to the Open Trust Protocol (OTrP), which influenced the design of this specification. B. Acknowledgements We would like to thank Eve Schooler for the suggestion of the protocol name. We would like to thank Kohei Isobe (TRASIO/SECOM), Ken Takayama (SECOM), Kuniyasu Suzaki (TRASIO/AIST), Tsukasa Oi (TRASIO), and Yuichi Takita (SECOM) for their valuable implementation feedback. We would also like to thank Carsten Bormann and Henk Birkholz for their help with the CDDL. Finally, we would like to thank the following IESG members for their review feedback: Sean Turner, Paul Kyzivat, Scott Hollenbeck, Luigi Iannone, Paul Wouters, and Yoshifumi Nishida C. Complete CDDL Valid TEEP messages adhere to the following CDDL data definitions, except that SUIT_Envelope and SUIT_Component_Identifier are specified in [I-D.ietf-suit-manifest]. This section is informative and merely summarizes the normative CDDL snippets in the body of this document. teep-message = $teep-message-type .within teep-message-framework teep-message-framework = [ type: $teep-type / $teep-type-extension, options: { * teep-option }, * any; further elements, e.g., for data-item-requested ] teep-option = (uint => any) ; messages defined below: Tschofenig, et al. Expires 5 August 2026 [Page 65] Internet-Draft TEEP Protocol February 2026 $teep-message-type /= query-request $teep-message-type /= query-response $teep-message-type /= update $teep-message-type /= teep-success $teep-message-type /= teep-error ; message type numbers, in one byte which could take a ; number from 0 to 23 $teep-type /= (0..23) TEEP-TYPE-query-request = 1 TEEP-TYPE-query-response = 2 TEEP-TYPE-update = 3 TEEP-TYPE-teep-success = 5 TEEP-TYPE-teep-error = 6 query-request = [ type: TEEP-TYPE-query-request, options: { ? token => bstr .size (8..64), ? supported-freshness-mechanisms => [ + $freshness-mechanism ], ? challenge => bstr .size (8..512), ? versions => [ + version ], ? attestation-payload-format => text, ? attestation-payload => bstr, ? suit-reports => [ + bstr .cbor SUIT_Report ], * $$query-request-extensions, * $$teep-option-extensions }, supported-teep-cipher-suites: [ + $teep-cipher-suite ], supported-suit-cose-profiles: [ + $suit-cose-profile ], data-item-requested: uint .bits data-item-requested ] version = uint .size 4 ext-info = uint .size 4 ; data items as bitmaps data-item-requested = &( attestation: 0, trusted-components: 1, extensions: 2, suit-reports: 3, ) ; teep-cipher-suites $teep-cipher-suite /= teep-cipher-suite-sign1-ed25519 $teep-cipher-suite /= teep-cipher-suite-sign1-esp256 Tschofenig, et al. Expires 5 August 2026 [Page 66] Internet-Draft TEEP Protocol February 2026 ;The following two cipher suites have only a single operation each. ;Other cipher suites may be defined to have multiple operations. ;It is MANDATORY for TAM to support them, and OPTIONAL ;to support any additional ones that use COSE_Sign_Tagged, or other ;signing, encryption, or MAC algorithms. teep-operation-sign1-ed25519 = [ cose-sign1, cose-alg-ed25519 ] teep-operation-sign1-esp256 = [ cose-sign1, cose-alg-esp256 ] teep-cipher-suite-sign1-ed25519 = [ teep-operation-sign1-ed25519 ] teep-cipher-suite-sign1-esp256 = [ teep-operation-sign1-esp256 ] ;MANDATORY for TAM and TEEP Agent to support the following COSE ;operations, and OPTIONAL to support additional ones such as ;COSE_Sign_Tagged, COSE_Encrypt0_Tagged, etc. cose-sign1 = 18 ; CoAP Content-Format value ;MANDATORY for TAM to support the following, and OPTIONAL to ;implement any additional algorithms from the IANA COSE Algorithms ;registry. cose-alg-esp256 = -9 ; ECDSA using P-256 curve and SHA-256 cose-alg-ed25519 = -19 ; EdDSA using Ed25519 curve ; suit-cose-profile $suit-cose-profile /= suit-sha256-esp256-ecdh-a128ctr $suit-cose-profile /= suit-sha256-ed25519-ecdh-a128ctr $suit-cose-profile /= suit-sha256-esp256-ecdh-a128gcm $suit-cose-profile /= suit-sha256-ed25519-ecdh-chacha-poly ; freshness-mechanisms FRESHNESS_NONCE = 0 FRESHNESS_TIMESTAMP = 1 $freshness-mechanism /= FRESHNESS_NONCE $freshness-mechanism /= FRESHNESS_TIMESTAMP query-response = [ type: TEEP-TYPE-query-response, options: { ? token => bstr .size (8..64), ? selected-version => version, ? attestation-payload-format => text, ? attestation-payload => bstr, ? suit-reports => [ + bstr .cbor SUIT_Report ], ? tc-list => [ + system-property-claims ], ? requested-tc-list => [ + requested-tc-info ], Tschofenig, et al. Expires 5 August 2026 [Page 67] Internet-Draft TEEP Protocol February 2026 ? unneeded-manifest-list => [ + SUIT_Component_Identifier ], ? ext-list => [ + ext-info ], * $$query-response-extensions, * $$teep-option-extensions } ] requested-tc-info = { component-id => SUIT_Component_Identifier, ? tc-manifest-sequence-number => uint, ? have-binary => bool } update = [ type: TEEP-TYPE-update, options: { ? token => bstr .size (8..64), ? unneeded-manifest-list => [ + SUIT_Component_Identifier ], ? manifest-list => [ + bstr .cbor SUIT_Envelope ], ? attestation-payload-format => text, ? attestation-payload => bstr, ? err-code => (0..23), ? err-msg => text .size (1..128), ? err-lang => text .size (1..35), * $$update-extensions, * $$teep-option-extensions } ] teep-success = [ type: TEEP-TYPE-teep-success, options: { ? token => bstr .size (8..64), ? msg => text .size (1..128), ? suit-reports => [ + bstr .cbor SUIT_Report ], * $$teep-success-extensions, * $$teep-option-extensions } ] teep-error = [ type: TEEP-TYPE-teep-error, options: { ? token => bstr .size (8..64), ? err-msg => text .size (1..128), ? err-lang => text .size (1..35), ? supported-teep-cipher-suites => [ + $teep-cipher-suite ], ? supported-freshness-mechanisms => [ + $freshness-mechanism ], Tschofenig, et al. Expires 5 August 2026 [Page 68] Internet-Draft TEEP Protocol February 2026 ? supported-suit-cose-profiles => [ + $suit-cose-profile ], ? challenge => bstr .size (8..512), ? versions => [ + version ], ? suit-reports => [ + bstr .cbor SUIT_Report ], * $$teep-error-extensions, * $$teep-option-extensions }, err-code: (0..23) ] ; The err-code parameter, uint (0..23) ERR_PERMANENT_ERROR = 1 ERR_UNSUPPORTED_EXTENSION = 2 ERR_UNSUPPORTED_FRESHNESS_MECHANISMS = 3 ERR_UNSUPPORTED_MSG_VERSION = 4 ERR_UNSUPPORTED_CIPHER_SUITES = 5 ERR_BAD_CERTIFICATE = 6 ERR_ATTESTATION_REQUIRED = 7 ERR_UNSUPPORTED_SUIT_REPORT = 8 ERR_CERTIFICATE_EXPIRED = 9 ERR_TEMPORARY_ERROR = 10 ERR_MANIFEST_PROCESSING_FAILED = 17 ; labels of mapkey for teep message parameters, uint (0..23) supported-teep-cipher-suites = 1 challenge = 2 versions = 3 supported-suit-cose-profiles = 4 selected-version = 6 attestation-payload = 7 tc-list = 8 ext-list = 9 manifest-list = 10 msg = 11 err-msg = 12 attestation-payload-format = 13 requested-tc-list = 14 unneeded-manifest-list = 15 component-id = 16 tc-manifest-sequence-number = 17 have-binary = 18 suit-reports = 19 token = 20 supported-freshness-mechanisms = 21 err-lang = 22 err-code = 23 Tschofenig, et al. Expires 5 August 2026 [Page 69] Internet-Draft TEEP Protocol February 2026 D. Examples of Diagnostic Notation and Binary Representation This section includes some examples with the following assumptions: * The device will have two TCs with the following SUIT Component Identifiers: - [ 0x000102030405060708090a0b0c0d0e0f ] - [ 0x100102030405060708090a0b0c0d0e0f ] * SUIT manifest-list is set empty only for example purposes (see Appendix E for actual manifest examples) D.1. QueryRequest Message D.1.1. CBOR Diagnostic Notation / query-request = / [ / type: / 1 / TEEP-TYPE-query-request /, / options: / { / token / 20 : h'A0A1A2A3A4A5A6A7A8A9AAABACADAEAF', / versions / 3 : [ 0 ] / 0 is current TEEP Protocol / }, / supported-teep-cipher-suites: / [ [ [ 18, -9 ] ] / Sign1 using ESP256 /, [ [ 18, -19 ] ] / Sign1 using Ed25519 / ], / supported-suit-cose-profiles: / [ [-16, -9, -29, -65534] / suit-sha256-esp256-ecdh-a128ctr /, [-16, -19, -29, -65534] / suit-sha256-ed25519-ecdh-a128ctr /, [-16, -9, -29, 1] / suit-sha256-esp256-ecdh-a128gcm /, [-16, -19, -29, 24] / suit-sha256-ed25519-ecdh-chacha-poly / ], / data-item-requested: / 3 / attestation | trusted-components / ] D.1.2. CBOR Binary Representation Tschofenig, et al. Expires 5 August 2026 [Page 70] Internet-Draft TEEP Protocol February 2026 =============== NOTE: '\' line wrapping per RFC 8792 ================ 85 # array(5) 01 # unsigned(1) / TEEP-TYPE-query-request / A2 # map(2) 14 # unsigned(20) / token: / 50 # bytes(16) A0A1A2A3A4A5A6A7A8A9AAABACADAEAF 03 # unsigned(3) / versions: / 81 # array(1) / [ 0 ] / 00 # unsigned(0) 82 # array(2) / supported-teep-cipher-suites / 81 # array(1) 82 # array(2) 12 # unsigned(18) / cose-sign1 / 28 # negative(8) / -9 = cose-alg-esp256 / 81 # array(1) 82 # array(2) 12 # unsigned(18) / cose-sign1 / 32 # negative(18) / -19 = cose-alg-ed25519 / 84 # array(4) / supported-suit-cose-profiles / 84 # array(4) / suit-sha256-esp256-ecdh-a128ctr /, 2f # negative(15) / -16 = SHA-256 / 28 # negative(8) / -9 = ESP256 / 38 1C # negative(28) / -29 = ECDH-ES + A128KW / 39 fffd # negative(65533) / -65534 = A128CTR / 84 # array(4) / suit-sha256-ed25519-ecdh-a128ctr / 2f # negative(15) / -16 = SHA-256 / 32 # negative(18) / -19 = Ed25519 / 38 1C # negative(28) / -29 = ECDH-ES + A128KW / 39 fffd # negative(65533) / -65534 = A128CTR / 84 # array(4) / suit-sha256-esp256-ecdh-a128gcm / 2f # negative(15) / -16 = SHA-256 / 28 # negative(6) / -9 = ESP256 / 38 1C # negative(28) / -29 = ECDH-ES + A128KW / 01 # unsigned(1) / A128GCM / 84 # array(4) / suit-sha256-ed25519-ecdh-chacha-\ poly / 2f # negative(15) / -16 = SHA-256 / 32 # negative(18) / Ed25519 / 38 1C # negative(28) / -29 = ECDH-ES + A128KW / 18 18 # unsigned(24) / 24 = ChaCha20/Poly1305 / 03 # unsigned(3) / attestation | trusted-\ components / Tschofenig, et al. Expires 5 August 2026 [Page 71] Internet-Draft TEEP Protocol February 2026 D.2. Entity Attestation Token This is shown below in CBOR diagnostic form. Only the payload signed by COSE is shown. D.2.1. CBOR Diagnostic Notation / eat-claim-set = / { / cnf / 8: { / kid / 3 : h'ba7816bf8f01cfea414140de5dae2223' h'b00361a396177a9cb410ff61f20015ad' }, / eat_nonce / 10: h'948f8860d13a463e8e', / ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea', / oemid / 258: h'894823', / IEEE OUI format OEM ID / / hwmodel / 259: h'549dcecc8b987c737b44e40f7c635ce8' / Hash of chip model name /, / hwversion / 260: ["1.3.4", 1], / Multipart numeric / / manifests / 273: [ [ 60, / application/cbor, TO BE REPLACED / / with the format value for a / / SUIT_Reference once one is allocated / { / SUIT_Reference / / suit-report-manifest-uri / 1: "https://example.com/manifest.cbor", / suit-report-manifest-digest / 0:[ / algorithm-id / -16 / "sha256" /, / digest-bytes / h'a7fd6593eac32eb4be578278e6540c5c' h'09cfd7d4d234973054833b2b93030609' ] } ] ] } D.3. QueryResponse Message D.3.1. CBOR Diagnostic Notation Tschofenig, et al. Expires 5 August 2026 [Page 72] Internet-Draft TEEP Protocol February 2026 =============== NOTE: '\' line wrapping per RFC 8792 ================ / query-response = / [ / type: / 2 / TEEP-TYPE-query-response /, / options: / { / token / 20 : h'A0A1A2A3A4A5A6A7A8A9AAABACADAEAF', / selected-version / 6 : 0, / attestation-payload / 7 : h'' / empty only for example \ purpose /, / tc-list / 8 : [ { / system-component-id / 0 : [ h'\ 0102030405060708090A0B0C0D0E0F' ], / suit-parameter-image-digest / 3: << [ / suit-digest-algorithm-id / -16 / SHA256 /, / suit-digest-bytes / h'\ A7FD6593EAC32EB4BE578278E6540C5C09CFD7D4D234973054833B2B93030609' / SHA256 digest of tc binary / ] >> } ] } ] D.3.2. CBOR Binary Representation Tschofenig, et al. Expires 5 August 2026 [Page 73] Internet-Draft TEEP Protocol February 2026 =============== NOTE: '\' line wrapping per RFC 8792 ================ 82 # array(2) 02 # unsigned(2) / TEEP-TYPE-query-response / A4 # map(4) 14 # unsigned(20) / token: / 50 # bytes(16) A0A1A2A3A4A5A6A7A8A9AAABACADAEAF 06 # unsigned(6) / selected-version: / 00 # unsigned(0) 07 # unsigned(7) / attestation-payload: / 40 # bytes(0) # "" 08 # unsigned(8) / tc-list: / 81 # array(1) A2 # map(2) 00 # unsigned(0) / system-component-id: / 81 # array(1) 4F # bytes(15) 0102030405060708090A0B0C0D0E0F 03 # unsigned(3) / suit-parameter-image-digest: / 58 24 # bytes(36) \ 822F5820A7FD6593EAC32EB4BE578278E6540C5C09CFD7D4D234973054833B2B9303\ 0609 D.4. Update Message D.4.1. CBOR Diagnostic Notation =============== NOTE: '\' line wrapping per RFC 8792 ================ / update = / [ / type: / 3 / TEEP-TYPE-update /, / options: / { / token / 20 : h'A0A1A2A3A4A5A6A7A8A9AAABACADAEAF', / manifest-list / 10 : [ << / SUIT_Envelope / { / suit-authentication-wrapper / 2: << [ << [ / suit-digest-algorithm-id: / -16 / suit-cose-alg-\ sha256 /, / suit-digest-bytes: / h'\ DB601ADE73092B58532CA03FBB663DE49532435336F1558B49BB622726A2FEDD' ] >>, Tschofenig, et al. Expires 5 August 2026 [Page 74] Internet-Draft TEEP Protocol February 2026 << / COSE_Sign1_Tagged / 18( [ / protected: / << { / algorithm-id / 1: -7 / ES256 / } >>, / unprotected: / {}, / payload: / null, / signature: / h'\ 5B2D535A2B6D5E3C585C1074F414DA9E10BD285C99A33916DADE3ED38812504817AC\ 48B62B8E984EC622785BD1C411888BE531B1B594507816B201F6F28579A4' ] ) >> ] >>, / suit-manifest / 3: << { / suit-manifest-version / 1: 1, / suit-manifest-sequence-number / 2: 3, / suit-common / 3: << { / suit-components / 2: [ [ h'544545502D446576696365', / "TEEP-\ Device" / h'5365637572654653', / "SecureFS" / h'8D82573A926D4754935332DC29997F74', / tc-uuid / h'7461' / "ta" / ] ], / suit-common-sequence / 4: << [ / suit-directive-override-parameters / 20, { / suit-parameter-vendor-identifier / 1: h'\ C0DDD5F15243566087DB4F5B0AA26C2F', / suit-parameter-class-identifier / 2: h'\ DB42F7093D8C55BAA8C5265FC5820F4E', / suit-parameter-image-digest / 3: << [ / suit-digest-algorithm-id: / -16 / suit-cose-\ alg-sha256 /, / suit-digest-bytes: / h'\ 8CF71AC86AF31BE184EC7A05A411A8C3A14FD9B77A30D046397481469468ECE8' ] >>, / suit-parameter-image-size / 14: 20 }, / suit-condition-vendor-identifier / 1, 15, / suit-condition-class-identifier / 2, 15 ] >> } >>, / suit-install / 9: << [ / suit-directive-override-parameters / 20, { / suit-parameter-uri / 21: "https://example.org/\ 8d82573a-926d-4754-9353-32dc29997f74.ta" }, / suit-directive-fetch / 21, 15, Tschofenig, et al. Expires 5 August 2026 [Page 75] Internet-Draft TEEP Protocol February 2026 / suit-condition-image-match / 3, 15 ] >> } >> } >> ] / array of bstr wrapped SUIT_Envelope / } ] D.4.2. CBOR Binary Representation =============== NOTE: '\' line wrapping per RFC 8792 ================ 82 # array(2) 03 # unsigned(3) / TEEP-TYPE-update / A2 # map(2) 14 # unsigned(20) / token: / 50 # bytes(16) A0A1A2A3A4A5A6A7A8A9AAABACADAEAF 0A # unsigned(10) / manifest-list: / 81 # array(1) 59 014E # bytes(336) A2025873825824822F5820DB601ADE73092B58532CA03FBB663DE495 \ 32435336F1558B49BB622726A2FEDD584AD28443A10126A0F658405B2D53 \ 5A2B6D5E3C585C1074F414DA9E10BD285C99A33916DADE3ED38812504817 \ AC48B62B8E984EC622785BD1C411888BE531B1B594507816B201F6F28579 \ A40358D4A401010203035884A20281844B544545502D4465766963654853 \ 65637572654653508D82573A926D4754935332DC29997F74427461045854 \ 8614A40150C0DDD5F15243566087DB4F5B0AA26C2F0250DB42F7093D8C55 \ BAA8C5265FC5820F4E035824822F58208CF71AC86AF31BE184EC7A05A411 \ A8C3A14FD9B77A30D046397481469468ECE80E14010F020F0958458614A1 \ 15783B68747470733A2F2F6578616D706C652E6F72672F38643832353733 \ 612D393236642D343735342D393335332D3332646332393939376637342E 7461150F030F Tschofenig, et al. Expires 5 August 2026 [Page 76] Internet-Draft TEEP Protocol February 2026 D.5. Success Message D.5.1. CBOR Diagnostic Notation / teep-success = / [ / type: / 5 / TEEP-TYPE-teep-success /, / options: / { / token / 20 : h'A0A1A2A3A4A5A6A7A8A9AAABACADAEAF' } ] D.5.2. CBOR Binary Representation 82 # array(2) 05 # unsigned(5) / TEEP-TYPE-teep-success / A1 # map(1) 14 # unsigned(20) / token: / 50 # bytes(16) A0A1A2A3A4A5A6A7A8A9AAABACADAEAF D.6. Error Message D.6.1. CBOR Diagnostic Notation / teep-error = / [ / type: / 6 / TEEP-TYPE-teep-error /, / options: / { / token / 20 : h'A0A1A2A3A4A5A6A7A8A9AAABACADAEAF', / err-msg / 12 : "disk-full" }, / err-code: / 17 / ERR_MANIFEST_PROCESSING_FAILED / ] D.6.2. CBOR binary Representation Tschofenig, et al. Expires 5 August 2026 [Page 77] Internet-Draft TEEP Protocol February 2026 83 # array(3) 06 # unsigned(6) / TEEP-TYPE-teep-error / A2 # map(2) 14 # unsigned(20) / token: / 50 # bytes(16) A0A1A2A3A4A5A6A7A8A9AAABACADAEAF 0C # unsigned(12) / err-msg: / 69 # text(9) 6469736B2D66756C6C # "disk-full" 11 # unsigned(17) / ERR_MANIFEST_PROCESSING_FAILED / E. Examples of SUIT Manifests This section shows some examples of SUIT manifests described in Section 4.4. The examples are signed using the following ECDSA secp256r1 key with SHA256 as the digest function. COSE_Sign1 Cryptographic Key: -----BEGIN PRIVATE KEY----- MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgApZYjZCUGLM50VBC CjYStX+09jGmnyJPrpDLTz/hiXOhRANCAASEloEarguqq9JhVxie7NomvqqL8Rtv P+bitWWchdvArTsfKktsCYExwKNtrNHXi9OB3N+wnAUtszmR23M4tKiW -----END PRIVATE KEY----- The corresponding public key can be used to verify these examples: -----BEGIN PUBLIC KEY----- MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEhJaBGq4LqqvSYVcYnuzaJr6qi/Eb bz/m4rVlnIXbwK07HypLbAmBMcCjbazR14vTgdzfsJwFLbM5kdtzOLSolg== -----END PUBLIC KEY----- Example 1: SUIT Manifest pointing to URI of the Trusted Component Binary CBOR Diagnostic Notation of SUIT Manifest =============== NOTE: '\' line wrapping per RFC 8792 ================ / SUIT_Envelope / { / authentication-wrapper / 2: << [ << [ / digest-algorithm-id: / -16 / SHA256 /, / digest-bytes: / h'\ B39B52B0B747EA79588C190F567BFC2C8437BA8A73F7EA983182E79F0148D59B' ] >>, << / COSE_Sign1_Tagged / 18([ Tschofenig, et al. Expires 5 August 2026 [Page 78] Internet-Draft TEEP Protocol February 2026 / protected: / << { / algorithm-id / 1: -9 / ESP256 / } >>, / unprotected: / {}, / payload: / null, / signature: / h'\ B35BF8C5276ACF6131F4661E76A7F19945FF928A4B7D79572583E857C695DFD48725\ C1B8253EF6E805A9EEE9262CAAB61A09DF69CCBD996F2431BC2515EB59FF' ]) >> ] >>, / manifest / 3: << { / manifest-version / 1: 1, / manifest-sequence-number / 2: 3, / common / 3: << { / components / 2: [ [ 'TEEP-Device', 'SecureFS', h'8D82573A926D4754935332DC29997F74', / tc-uuid / 'ta' ] ], / shared-sequence / 4: << [ / directive-override-parameters / 20, { / parameter-vendor-identifier / 1: h'\ C0DDD5F15243566087DB4F5B0AA26C2F', / parameter-class-identifier / 2: h'\ DB42F7093D8C55BAA8C5265FC5820F4E', / parameter-image-digest / 3: << [ / digest-algorithm-id: / -16 / SHA256 /, / digest-bytes: / h'\ 8CF71AC86AF31BE184EC7A05A411A8C3A14FD9B77A30D046397481469468ECE8' ] >>, / parameter-image-size / 14: 20 }, / condition-vendor-identifier / 1, 15, / condition-class-identifier / 2, 15 ] >> } >>, / manifest-component-id / 5: [ 'TEEP-Device', 'SecureFS', h'8D82573A926D4754935332DC29997F74', / tc-uuid / 'suit' ], / install / 20: << [ / directive-override-parameters / 20, { / parameter-uri / 21: "https://example.org/8d82573a-926d-\ Tschofenig, et al. Expires 5 August 2026 [Page 79] Internet-Draft TEEP Protocol February 2026 4754-9353-32dc29997f74.ta" }, / directive-fetch / 21, 15, / condition-image-match / 3, 15 ] >>, / uninstall / 24: << [ / directive-unlink / 33, 15 ] >> } >> } CBOR Binary in Hex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xample 2: SUIT Manifest including the Trusted Component Binary CBOR Diagnostic Notation of SUIT Manifest =============== NOTE: '\' line wrapping per RFC 8792 ================ / SUIT_Envelope / { / authentication-wrapper / 2: << [ << [ / digest-algorithm-id: / -16 / SHA256 /, / digest-bytes: / h'\ CEDB0457952F7DD0A33FA4692F73BC833A6A6E2300B16F6605993F0192E3F219' ] >>, << / COSE_Sign1_Tagged / 18([ / protected: / << { / algorithm-id / 1: -9 / ESP256 / } >>, / unprotected: / {}, / payload: / null, / signature: / h'\ 6A9F4D3DE3B8BC49A47F12E13A3EF76C5E2B4BB1D8EE6EFFA659220A6D8D164B3926\ Tschofenig, et al. Expires 5 August 2026 [Page 80] Internet-Draft TEEP Protocol February 2026 A722220283A9C7B48DA012A188F0C6F98F3962613E63CD4C597D4C01F56C' ]) >> ] >>, / manifest / 3: << { / manifest-version / 1: 1, / manifest-sequence-number / 2: 3, / common / 3: << { / components / 2: [ [ 'TEEP-Device', 'SecureFS', h'8D82573A926D4754935332DC29997F74', / tc-uuid / 'ta' ] ], / shared-sequence / 4: << [ / directive-override-parameters / 20, { / parameter-vendor-identifier / 1: h'\ C0DDD5F15243566087DB4F5B0AA26C2F', / parameter-class-identifier / 2: h'\ DB42F7093D8C55BAA8C5265FC5820F4E', / parameter-image-digest / 3: << [ / digest-algorithm-id: / -16 / SHA256 /, / digest-bytes: / h'\ 8CF71AC86AF31BE184EC7A05A411A8C3A14FD9B77A30D046397481469468ECE8' ] >>, / parameter-image-size / 14: 20 }, / condition-vendor-identifier / 1, 15, / condition-class-identifier / 2, 15 ] >> } >>, / manifest-component-id / 5: [ 'TEEP-Device', 'SecureFS', h'8D82573A926D4754935332DC29997F74', / tc-uuid / 'suit' ], / install / 20: << [ / directive-override-parameters / 20, { / uri / 21: "#tc" }, / directive-fetch / 21, 15, / condition-image-match / 3, 15 ] >>, / uninstall / 24: << [ / directive-unlink / 33, 15 ] >> Tschofenig, et al. Expires 5 August 2026 [Page 81] Internet-Draft TEEP Protocol February 2026 } >>, "#tc" : 'Hello, Secure World!' } CBOR Binary in Hex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xample 3: Supplying Personalization Data for Trusted Component Binary This example uses the following parameters: * SUIT Profile: suit-sha256-esp256-ecdh-a128ctr (see [I-D.ietf-suit-mti] Section 3.2) - Algorithm for payload encryption: A128CTR (-65534) - Algorithm for key wrap: ECDH-ES + A128KW (-29) * KEK (Receiver's Private Key): - kty: EC2 - crv: P-256 - x: h'5886CD61DD875862E5AAA820E7A15274 C968A9BC96048DDCACE32F50C3651BA3' - y: h'9EED8125E932CD60C0EAD3650D0A485C F726D378D1B016ED4298B2961E258F1B' - d: h'60FE6DD6D85D5740A5349B6F91267EEA C5BA81B8CB53EE249E4B4EB102C476B3' * COSE_KDF_Context - AlgorithmID: -3 (A128KW) Tschofenig, et al. Expires 5 August 2026 [Page 82] Internet-Draft TEEP Protocol February 2026 - SuppPubInfo o keyDataLength: 128 o protected: << {/ alg / 1: -29 / ECDH-ES+A128KW / } >> o other: 'SUIT Payload Encryption' CBOR Diagnostic Notation of SUIT Manifest =============== NOTE: '\' line wrapping per RFC 8792 ================ / SUIT_Envelope / { / authentication-wrapper / 2: << [ << [ / digest-algorithm-id: / -16 / SHA256 /, / digest-bytes: / h'\ 506D4796D65AE599EE0A3F7D123ED6819E0FA1A324A5DE547F6D7F50D465508A' ] >>, << / COSE_Sign1_Tagged / 18([ / protected: / << { / algorithm-id / 1: -9 / ESP256 / } >>, / unprotected: / {}, / payload: / null, / signature: / h'\ 9AF4896B66B0642122C5317D1D8A81BB4CE3C0B022A7A53879224BA14AE954DE456D\ 01069DEF0B5CE2E6B0325ACF21B5059320ABBA8480602C8A6FD7BF7894FF' ]) >> ] >>, / manifest / 3: << { / manifest-version / 1: 1, / manifest-sequence-number / 2: 3, / common / 3: << { / dependencies / 1: { / component-index / 1: { / dependency-prefix / 1: [ 'TEEP-Device', 'SecureFS', h'8D82573A926D4754935332DC29997F74', / tc-uuid / 'suit' ] } }, / components / 2: [ [ 'TEEP-Device', 'SecureFS', Tschofenig, et al. Expires 5 August 2026 [Page 83] Internet-Draft TEEP Protocol February 2026 'config.json' ] ], / shared-sequence / 4: << [ / directive-set-component-index / 12, 0, / directive-override-parameters / 20, { / parameter-vendor-identifier / 1: h'\ C0DDD5F15243566087DB4F5B0AA26C2F', / parameter-class-identifier / 2: h'\ DB42F7093D8C55BAA8C5265FC5820F4E' }, / condition-vendor-identifier / 1, 15, / condition-class-identifier / 2, 15 ] >> } >>, / manifest-component-id / 5: [ 'TEEP-Device', 'SecureFS', 'config.suit' ], / validate / 7: << [ / directive-set-component-index / 12, 0, / directive-override-parameters / 20, { / NOTE: image-digest and image-size of plaintext config.\ json / / parameter-image-digest / 3: << [ / digest-algorithm-id: / -16 / SHA256 /, / digest-bytes: / h'\ 8273468FB64BD84BB04825F8371744D952B751C73A60F455AF681E167726F116' ] >>, / image-size / 14: 61 }, / condition-image-match / 3, 15 ] >>, / dependency-resolution / 15: << [ / directive-set-component-index / 12, 1, / directive-override-parameters / 20, { / parameter-image-digest / 3: << [ / algorithm-id / -16 / SHA256 /, / digest-bytes / h'\ B39B52B0B747EA79588C190F567BFC2C8437BA8A73F7EA983182E79F0148D59B' ] >>, / parameter-image-size / 14: 389, / parameter-uri / 21: "https://example.org/8d82573a-926d-\ 4754-9353-32dc29997f74.suit" }, / directive-fetch / 21, 2 ] >>, Tschofenig, et al. Expires 5 August 2026 [Page 84] Internet-Draft TEEP Protocol February 2026 / install / 20: << [ / directive-set-component-index / 12, 1, / directive-process-dependency / 11, 0, / NOTE: fetch encrypted firmware / / directive-set-component-index / 12, 0, / directive-override-parameters / 20, { / NOTE: encrypted payload and encryption-info / / parameter-content / 18: h'\ 6D5BE4F569E98AE01F38B071EF025437B742FF28854AB32C868BC6A76CD33B5CA112\ FF22BA95EA4672B7199C89A7829183794A21A6BE345C4371DCB0DC', / parameter-encryption-info / 19: << 96([ / protected: / h'', / unprotected: / { / alg / 1: -65534 / A128CTR /, / IV / 5: h'67E3BA7CD42D02BBC39C508B5EA0F1C4' }, / payload: / null / detached ciphertext /, / recipients: / [ [ / protected: / << { / alg / 1: -29 / ECDH-ES + A128KW / } >>, / unprotected: / { / ephemeral key / -1: { / kty / 1: 2 / EC2 /, / crv / -1: 1 / P-256 /, / x / -2: h'\ F2452399667F57993B14C5F1107F667884854C190894FC08531C1E2290A7BA19', / y / -3: h'\ 275EDDE29FD75C9393AFFA706F8FAD3C49D03D67D47F8B0C027BE5F0BCA884CB' } }, / payload: / h'\ 7D806DA1ACEC6F704D803F0CFE7420525C81E1957699FCCE' ] ] ]) >> }, / decrypt encrypted firmware / / directive-write / 18, 15 / consumes the \ SUIT_Encryption_Info above / / NOTE: decrypted payload would be ``{"name":"FOO Bar","secret\ ":"0123456789abfcdef0123456789abcd"}'' / ] >>, / uninstall / 24: << [ / directive-set-component-index / 12, 1, Tschofenig, et al. Expires 5 August 2026 [Page 85] Internet-Draft TEEP Protocol February 2026 / directive-process-dependency / 11, 0, / directive-set-component-index / 12, 0, / directive-unlink / 33, 15 ] >> } >> } CBOR Binary in Hex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xamples of SUIT Reports This section shows some examples of SUIT reports. F.1. Example 1: Success SUIT Reports have no records if no conditions have failed. The URI in this example is the reference URI provided in the SUIT manifest. Tschofenig, et al. Expires 5 August 2026 [Page 86] Internet-Draft TEEP Protocol February 2026 { / suit-report-manifest-digest / 1:<<[ / algorithm-id / -16 / "sha256" /, / digest-bytes / h'a7fd6593eac32eb4be578278e6540c5c' h'09cfd7d4d234973054833b2b93030609' ]>>, / suit-report-manifest-uri / 2: "tam.teep.example/personalisation", / suit-report-records / 4: [] } F.2. Example 2: Failure { / suit-report-manifest-digest / 1:<<[ / algorithm-id / -16 / "sha256" /, / digest-bytes / h'a7fd6593eac32eb4be578278e6540c5c09cfd7d4d23497 3054833b2b93030609' ]>>, / suit-report-manifest-uri / 2: "tam.teep.example/personalisation", / suit-report-records / 4: [ { / suit-record-manifest-id / 1:[], / suit-record-manifest-section / 2: 7 / dependency-resolution /, / suit-record-section-offset / 3: 66, / suit-record-dependency-index / 5: 0, / suit-record-failure-reason / 6: 404 } ] } where the dependency-resolution refers to: { authentication-wrapper, / manifest / 3:<<{ / manifest-version / 1:1, / manifest-sequence-number / 2:3, common, dependency-resolution, install, validate, run, text }>>, } and the suit-record-section-offset refers to: Tschofenig, et al. Expires 5 August 2026 [Page 87] Internet-Draft TEEP Protocol February 2026 <<[ / directive-set-dependency-index / 13,0, / directive-set-parameters / 19,{ / uri / 21:'tam.teep.example/' 'edd94cd8-9d9c-4cc8-9216-b3ad5a2d5b8a', } , / directive-fetch / 21,2, / condition-image-match / 3,15 ]>>, Authors' Addresses Hannes Tschofenig University of Applied Sciences Bonn-Rhein-Sieg Germany Email: hannes.tschofenig@gmx.net Mingliang Pei Broadcom United States of America Email: mingliang.pei@broadcom.com David Wheeler Amazon United States of America Email: davewhee@amazon.com Dave Thaler Microsoft United States of America Email: dave.thaler.ietf@gmail.com Akira Tsukamoto Openchip & Software Technologies, S.L. Spain Email: akira.tsukamoto@gmail.com Tschofenig, et al. Expires 5 August 2026 [Page 88]