# Editor, SD-JWT and SD-JWT VC

Source: https://startwithidentity.com/experts/daniel-fett/
Last updated: 2026-09-20
License: content by Start with Identity. Cite the source URL.

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## Bio

Daniel Fett did a PhD on formal methods for analyzing web security and then pointed those methods at the protocols this industry depends on, finding attacks on OAuth and OpenID Connect that human review had missed. He led the formal analysis of [FAPI](https://startwithidentity.com/standards/fapi/) 1.0, co-authored the OAuth 2.0 Security Best Current Practice and FAPI 2.0, and edits the SD-JWT and SD-JWT VC specifications.

Profile built from public IETF, OpenID Foundation, and academic records.

## Where their work shows up

Two distinct contributions. First, proof: a formal model that says a protocol is secure under stated assumptions is a different kind of claim from a working group's confidence, and [OAuth 2.1](https://startwithidentity.com/standards/oauth-2-1/) and FAPI 2.0 both carry that work. Second, SD-JWT, which is how a [verifiable credential](https://startwithidentity.com/standards/verifiable-credentials/) can be issued once and then presented with only some fields revealed, with the rest cryptographically hidden rather than merely omitted. That is the mechanism behind selective disclosure in the [EUDI wallet](https://startwithidentity.com/standards/eidas-2-eudi-wallet/) and [OpenID4VC](https://startwithidentity.com/standards/openid4vc/).