[OAUTH-WG] SD-JWT + Unlinkability: A TEE-based Approach for Private Attribute Disclosure

[Wayne Chang <[e-mail]>]

Hi all,

I think it's important that a workable approach to privacy is made
available to all active implementers of verifiable digital credential
systems, while meeting standards-based hardware assurance requirements for
issuers like FIPS and CMVP.

I have recently presented this TEE-based approach that could add
unlinkability to SD-JWT, ISO mDL/mdoc, etc. for attribute disclosure with a
straightforward upgrade path to existing installations (11+ mDL programs
live in the US). This approach would be compatible with FIPS 140-2/3
requirements and also PQC. It could be used alongside ZKP-in-the-wallet
approaches as well.

I thought that people on this list might be interested given the recent
discussion around the various verifier-verifier and issuer-verifier
collusions. You can find the slides in the first link below. For those
preparing their stones to cast at TEE approaches, please take a look at the
slides first, which describe defense-in-depth as a requirement to implement
this safely.

NIST Workshop on Privacy-Enhancing Cryptography 2024 Page:
https://csrc.nist.gov/Presentations/2024/wpec2024-3b4

Original blog post:
https://blog.spruceid.com/provably-forgotten-signatures-adding-privacy-to-digital-identity/

I'm currently working on formalizing some assumptions for specific
hardware, environments, and protocols--please let me know if you'd like to
get involved and/or collaborate on this.

Best,
- Wayne