Musings on Digital Identity

Month: September 2017

Initial Working Group Draft of Proof-of-Possession Key Semantics for CBOR Web Tokens (CWTs)

IETF logoThe initial working group draft of the Proof-of-Possession Key Semantics for CBOR Web Tokens (CWTs) specification has been posted. It contains the same normative content as draft-jones-ace-cwt-proof-of-possession-01. The abstract of the specification is:

This specification describes how to declare in a CBOR Web Token (CWT) that the presenter of the CWT possesses a particular proof-of-possession key. Being able to prove possession of a key is also sometimes described as the presenter being a holder-of-key. This specification provides equivalent functionality to “Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs)” (RFC 7800), but using CBOR and CWTs rather than JSON and JWTs.

I look forward to working with my co-authors and the working group to hopefully complete this quickly!

The specification is available at:

An HTML-formatted version is also available at:

“Using RSA Algorithms with CBOR Object Signing and Encryption (COSE) Messages” is now RFC 8230

IETF logoThe “Using RSA Algorithms with CBOR Object Signing and Encryption (COSE) Messages” specification is now RFC 8230 – an IETF standard. The abstract for the specification is:

The CBOR Object Signing and Encryption (COSE) specification defines cryptographic message encodings using Concise Binary Object Representation (CBOR). This specification defines algorithm encodings and representations enabling RSA algorithms to be used for COSE messages. Encodings are specified for the use of RSA Probabilistic Signature Scheme (RSASSA-PSS) signatures, RSA Encryption Scheme – Optimal Asymmetric Encryption Padding (RSAES-OAEP) encryption, and RSA keys.

Some of these values are already being used by the sixth working draft of the W3C Web Authentication specification. In addition, the WebAuthn specification defines algorithm values for RSASSA-PKCS1-v1_5 signatures, which are used by TPMs, among other applications. The RSASSA-PKCS1-v1_5 signature algorithm values should also be registered shortly.

Thanks to Kathleen Moriarty for her Area Director sponsorship of the specification!

OAuth Authorization Server Metadata spec incorporating Area Director feedback

OAuth logoThe OAuth Authorization Server Metadata specification has been updated to incorporate feedback from Security Area Director Eric Rescorla. Thanks to EKR for his useful review. A number of defaults and restrictions are now better specified.

The specification is available at:

An HTML-formatted version is also available at:

Powered by WordPress & Theme by Anders Norén