Registration Data Access Protocol (RDAP) Extension for Verified Contact Information

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Table of Contents

1. Introduction

The Registration Data Access Protocol (RDAP) provides access to registration data for domain names, IP addresses, and autonomous system numbers. However, RDAP responses do not currently include explicit information about whether contact information such as email addresses or phone numbers has been verified.¶

This document defines a simple extension that enables RDAP providers to include verification status for contact fields. This is useful in contexts where contact verification may be legally required or strongly recommended.¶

In particular, Article 28 of Directive (EU) 2022/2555 ([NIS2]) requires top-level domain (TLD) name registries and domain name registrars to collect and maintain accurate and complete domain name registration data. It also mandates them to verify, to the extent possible, the accuracy of such data. The extension defined in this document can support compliance with this obligation by enabling the inclusion of verification status for contact fields in RDAP responses.¶

2. Conventions Used in This Document

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.¶

3. RDAP Conformance

Servers implementing this extension MUST include the string "verifiedContacts" in the "rdapConformance" ([RFC9083]) array of all relevant RDAP responses. The registration of the "verifiedContacts" extension identifier is described in Section 7.¶

4. JSON Structure

The verification information is conveyed via a new top-level object member named "verifiedContacts_data" within the entity objects.¶

      {
        "objectClassName": "entity",
        "handle": "ABC123-EXAMPLE",
        "rdapConformance": ["rdap_level_0", "verifiedContacts"],
        ...
        "verifiedContacts_data": {
          "email": {
            "verificationDate": "2025-03-15T12:00:00Z",
            "method": "email verification"
          }
          ...
        }
      }

5. verifiedContacts_data Structure

The "verifiedContacts_data" member is an object whose keys are contact details, using one of the RDAP JSON Values Registry "verified contact detail" type values (e.g., "all", "email", "voice", "fax", "addr"). Each value is an object containing:¶

"verificationDate":

(REQUIRED) Date and time of verification, as defined in [RFC3339].¶

"method":

(OPTIONAL) Verification method, using one of the RDAP JSON Values Registry “verified contact method” type values. The initial set of “verified contact method” values are:¶

"email verification":

Sending a confirmation link to the specified email address and requiring user interaction (e.g., clicking the link) to confirm ownership.¶

"sms token":

Sending a one-time token (OTP) via SMS to the provided phone number and requiring the user to submit the token to confirm ownership.¶

"manual review":

Manual review of contact data by a human operator (e.g., calling the phone number, making a live video call, inspecting submitted documentation).¶

"eid validation":

Validation of contact data using a digital identity service, either before or after registration (e.g., eIDAS-compliant identity providers).¶

"address verification":

Verification of the postal address using a geolocation or address validation service (e.g., Google Maps API, OpenStreetMap, postal databases).¶

"cross validation":

Cross-checking of contact details (e.g., name, VAT number, postal address) against trusted third-party repositories (e.g., EU VIES).¶

"third party assertion":

Relying on a trusted third party (e.g., registrar, CSP, certification authority) to assert that contact data has been verified externally.¶

"verifierId":

(OPTIONAL) Verifier identifier, that is a server unique number or a delimited string using a '-' as a separator character to support a regional or globally unique identifier. The minimum length is 1 character and the maximum length is 40 characters. The set of verifiers and verifier identifiers is up to server policy.¶

"verifierName":

(OPTIONAL) Verifier name of the verifier that is a simple character string, with a minimum length of 1 character and a maximum length of 40 characters. The set of verifiers and verifier identifiers is up to server policy.¶

"verificationId":

(OPTIONAL) Verification identifier that is unique for the verification performed by the verifier, that is represented as a number with the option of a '-' separator for grouping verifications by region or verifier. The minimum length is 1 character and the maximum length is 40 characters. For example, the "verificationId" could follow the Augmented Backus-Naur Form (ABNF) grammar [RFC5234] scheme verifierId "-" verificationNumber, where the "verificationNumber" is unique to the "verifierId", making the "verificationId" unique across many verifiers supported by the server.¶

6. Extension Version Identifier

This extension supports the following versioning types as defined in [I-D.ietf-regext-rdap-versioning]:¶

• Opaque Versioning: The Opaque Extension Version Identifier is "verifiedContacts".¶
• Semantic Versioning: The Semantic Extension Version Identifier is "verifiedContacts-0.3". The Semantic Extension Version Identifier is "verifiedContacts-0.2" for draft-loffredo-regext-rdap-verified-contacts-02 and "verifiedContacts-0.1" for draft-loffredo-regext-rdap-verified-contacts-01. When there are interface changes to the extension, the Semantic Extension Version Identifier will be incremented, which may not match the draft version number. When the draft becomes a working group document and passes Working Group Last Call (WGLC), the Semantic Extension Version Identifier will be changed to "verifiedContacts-1.0".¶

7. IANA Considerations

8. Security Considerations

Contact verification data may have privacy implications. Servers MUST ensure that disclosure of this information complies with applicable data protection laws and policies.¶

9. Acknowledgements

The authors wish to thank the following persons for their feedback and suggestions: Scott Hollenbeck.¶

Authors' Addresses