| oidc-esid | June 2025 | |
| Sakimura & Jay | Standards Track | [Page] |
OpenID Connect specifies the public and pairwise subject identifier types. These types of subject identifiers allow relying parties to keep track of the End-User across multiple visits to the relying party application by correlating the subject identifier. This document specifies an ephemeral subject identifier type that prevents correlation of the subject identifier across multiple visits to enhance user privacy.¶
This document is not an OIDF International Standard. It is distributed for review and comment. It is subject to change without notice and may not be referred to as an International Standard.¶
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation.¶
The OpenID Foundation (OIDF) promotes, protects and nurtures the OpenID community and technologies. As a non-profit international standardizing body, it is comprised by over 160 participating entities (workgroup participants). The work of preparing implementer drafts and final international standards is carried out through OIDF workgroups in accordance with the OpenID Process. Participants interested in a subject for which a workgroup has been established has the right to be represented in that workgroup. International organizations, governmental and non-governmental, in liaison with OIDF, also take part in the work. OIDF collaborates closely with other standardizing bodies in the related fields.¶
This document specifies an ephemeral subject identifier type for OpenID Connect Core 1.0. The ephemeral subject identifier identifies the End-User for a short time and remains constant for the duration of the authentication session. In subsequent visits by the End-User to a Relying Party application that requires authentication, the authorization server will return a subject identifier with a different value. The authorization server provides an ephemeral subject identifier to the Relying Party in the ID Token and UserInfo endpoint response as specified by OpenID Connect Core 1.0.¶
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 when, and only when, they appear in all capitals, as shown here.¶
In the .txt version of this document, values are quoted to indicate that they are to be taken literally. When using these values in protocol messages, the quotes MUST NOT be used as part of the value. In the HTML version of this document, values to be taken literally are indicated by the use of this fixed-width font.¶
For the purpose of this document, the terms defined in RFC6749, and OpenID Connect Core 1.0 apply.¶
This document adds a new subject identifier type as follows, in addition to what is defined in Section 8 of OpenID Connect Core 1.0:¶
The OpenID Provider indicates support for ephemeral subject identifiers in the metadata document.¶
This document defines the following new value for the subject_types_supported metadata of OpenID Discovery 1.0:¶
The RP requests the OP to return ephemeral subject identifiers by registering ephemeral as the subject_type in OpenID Dynamic Registration 1.0 or by other means.¶
The generated ephemeral identifier needs to be unique over time. Otherwise, the RP may link two different users to the same record and will cause a security incident. One way to achieve uniqueness is to use the hash of the combination of a cryptographic random and the timestamp as the sub value.¶
The privacy objectives of this document are as follows:¶
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applied. For undated references, the latest edition of the referenced document (including any amendments) applies.¶
BCP14 - Key words for use in RFCs to Indicate Requirement Levels¶
RFC2119 - Key words for use in RFCs to Indicate Requirement Levels¶
RFC8174 - Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words¶
RFC6749 - The OAuth 2.0 Authorization Framework¶
OIDC - OpenID Connect Core 1.0 incorporating errata set 1¶
OpenID.Discovery - OpenID Connect Discovery 1.0¶
OpenID.Registration - OpenID Connect Registration 1.0¶
The OpenID Foundation (OIDF) grants to any Contributor, developer, implementer, or other interested party a non-exclusive, royalty free, worldwide copyright license to reproduce, prepare derivative works from, distribute, perform and display, this Implementers Draft or Final Specification solely for the purposes of (i) developing specifications, and (ii) implementing Implementers Drafts and Final Specifications based on such documents, provided that attribution be made to the OIDF as the source of the material, but that such attribution does not indicate an endorsement by the OIDF.¶
The technology described in this specification was made available from contributions from various sources, including members of the OpenID Foundation and others. Although the OpenID Foundation has taken steps to help ensure that the technology is available for distribution, it takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this specification or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any independent effort to identify any such rights. The OpenID Foundation and the contributors to this specification make no (and hereby expressly disclaim any) warranties (express, implied, or otherwise), including implied warranties of merchantability, non-infringement, fitness for a particular purpose, or title, related to this specification, and the entire risk as to implementing this specification is assumed by the implementer. The OpenID Intellectual Property Rights policy requires contributors to offer a patent promise not to assert certain patent claims against other contributors and against implementers. The OpenID Foundation invites any interested party to bring to its attention any copyrights, patents, patent applications, or other proprietary rights that may cover technology that may be required to practice this specification.¶