| RFC 9560 | OIDC for RDAP | April 2024 |
| Hollenbeck | Standards Track | [Page] |
The Registration Data Access Protocol (RDAP) provides Representational State Transfer (RESTful) web services to retrieve registration metadata from domain name and regional internet registries. RDAP allows a server to make access control decisions based on client identity, and as such, it includes support for client identification features provided by the Hypertext Transfer Protocol (HTTP). Identification methods that require clients to obtain and manage credentials from every RDAP server operator present management challenges for both clients and servers, whereas a federated authentication system would make it easier to operate and use RDAP without the need to maintain server-specific client credentials. This document describes a federated authentication system for RDAP based on OpenID Connect.¶
This is an Internet Standards Track document.¶
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.¶
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc9560.¶
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The Registration Data Access Protocol (RDAP) provides Representational State Transfer (RESTful) web services to retrieve registration metadata from domain name and regional internet registries. RDAP allows a server to make access control decisions based on client identity, and as such, it includes support for client identification features provided by the Hypertext Transfer Protocol (HTTP) [RFC9110].¶
RDAP is specified in multiple documents, including "HTTP Usage in the Registration Data Access Protocol (RDAP)" [RFC7480], "Security Services for the Registration Data Access Protocol (RDAP)" [RFC7481], "Registration Data Access Protocol (RDAP) Query Format" [RFC9082], and "JSON Responses for the Registration Data Access Protocol (RDAP)" [RFC9083]. [RFC7481] describes client identification and authentication services that can be used with RDAP, but it does not specify how any of these services can (or should) be used with RDAP.¶
The conventional "username and password" authentication method does not scale well in the RDAP ecosystem. Assuming that all domain name and address registries will eventually provide RDAP service, it is impractical and inefficient for users to secure login credentials from the hundreds of different server operators. Authentication methods based on usernames and passwords do not provide information that describes the user in sufficient detail (while protecting the personal privacy of the user) for server operators to make fine-grained access control decisions based on the user's identity. The authentication system used for RDAP needs to address all of these needs.¶
A basic level of RDAP service can be provided to users who possess an identifier issued by a recognized provider who can authenticate and validate the user. For example, the identifiers issued by social media services can be used. Users who require higher levels of service (and who are willing to share more information about themselves to gain access to that service) can secure identifiers from specialized providers who are or will be able to provide more detailed information about the user. Server operators can then make access control decisions based on the identification information provided by the user.¶
A federated authentication system in which an RDAP server outsources identification and authentication services to a trusted identity provider would make it easier to operate and use RDAP by reusing existing identifiers to provide a basic level of access. It can also provide the ability to collect additional user identification information, and that information can be shared with the RDAP server operator with the consent of the user in order to help the server operator make access control decisions. This type of system allows an RDAP server to make access control decisions based on the nature of a query and the identity, authentication, and authorization information that is received from the identity provider. This document describes a federated authentication system for RDAP based on OpenID Connect [OIDC] that meets these needs.¶
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.¶
All of the HTTP requests described in this document that are sent from an RDAP client to an RDAP server use the HTTP GET method as specified in [RFC9110].¶
Long lines in examples are wrapped using "The Single Backslash Strategy" described in [RFC8792].¶
RDAP itself does not include built-in security services. Instead, RDAP relies on features that are available in other protocol layers to provide needed security services including access control, authentication, authorization, availability, data confidentiality, data integrity, and identification. A description of each of these security services can be found in "Internet Security Glossary, Version 2" [RFC4949]. This document focuses on a federated authentication system for RDAP that provides services for authentication, authorization, and identification, allowing a server operator to make access control decisions. Section 3 of [RFC7481] describes general considerations for RDAP access control, authentication, and authorization.¶
The conventional client-server authentication model requires clients to maintain distinct credentials for every RDAP server. This situation can become unwieldy as the number of RDAP servers increases. Federated authentication mechanisms allow clients to use one credential to access multiple RDAP servers and reduce client credential management complexity.