SD-JWT Support in JWSETKit — Privacy-Preserving Credentials for Swift

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Hey everyone! :waving_hand:

Wanted to share that JWSETKit now has full SD-JWT (Selective Disclosure JWT) support, implementing RFC 9901.

What's SD-JWT? It lets you issue credentials where users can selectively reveal only the claims they need that is great for privacy-preserving identity use cases like digital wallets (e.g. European Digital Identity), verifiable credentials (e.g. SD-JWT VC draft and W3C VC), and OIDC flows.

Quick example:

import JWSETKit

// Issuer: Create SD-JWT with selective claims
let claims = try JSONWebTokenClaims {
    $0.issuer = "https://issuer.example.com"
    $0.subject = "user123"
    $0.givenName = "John"
    $0.familyName = "Doe"
    $0.email = "john@example.com"
}

let sdJWT = try JSONWebSelectiveDisclosureToken(
    claims: claims,
    policy: .standard,
    using: issuerKey
)

// Holder: Present only what's needed
let presentation = try sdJWT.presenting(paths: ["/email"])

// Verifier: Validate and access presented disclosed claims
try presentation.verifySignature(using: issuerPublicKey)
let disclosed = try presentation.disclosedPayload
let email = disclosed.email

If you're already using JWSETKit for JWT/JWS/JWE, SD-JWT fits right in with the same patterns.

For those unfamiliar, JWSETKit is a full JOSE implementation with native CryptoKit support. We went through the SSWG review process and have been iterating based on that feedback (now using swift-crypto exclusively).

Links:

Questions and feedback welcome!

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