SD-JWT VC primitives

Low-level building blocks exported from @owlid/sdk. Most apps use OwlVerifier, OwlIssuer, or OwlWallet instead — reach for these primitives only when you need direct control over key material or the SD-JWT VC wire format.

All of it is pure TypeScript (@noble/ed25519 + @noble/hashes) — no WASM, no native binaries. Output is standard SD-JWT VC, accepted by any conformant verifier.

import { KeyPair, PublicKey, SdJwtVc, presentSdJwtVc, verifySdJwt } from '@owlid/sdk'

`KeyPair`

A holder signing key (Ed25519). The wallet keeps the 32-byte seed PRF-wrapped by the passkey — see Holder integration.

const key = KeyPair.generate() // fresh random key
const same = KeyPair.fromHex(seedHex) // restore from a stored seed

key.toHex() // 32-byte private seed, hex — persist this (wrapped)
key.publicKeyHex() // public key, hex — goes in the credential `cnf`

Member	Returns	Notes
`KeyPair.generate()`	`KeyPair`	New random Ed25519 key.
`KeyPair.fromHex(h)`	`KeyPair`	Restore from a 32-byte seed hex.
`.toHex()`	`string`	Private seed hex. Store wrapped, never bare.
`.publicKeyHex()`	`string`	Public key hex.

`PublicKey`

const pk = PublicKey.fromHex(hex)
pk.toHex() // hex string

`SdJwtVc`

Parsed view of an SD-JWT VC string (<JWT>~<disclosure>~…~<KB-JWT>).

const vc = SdJwtVc.parse(storedCredential.sdJwtVc)

vc.peekIssuer() // `iss` claim — did:web identifier
vc.credentialId() // stable id (base64url) used for revocation lookups
vc.disclosedClaimNames() // names of the disclosures present on this string
vc.disclosedClaim('given_name') // a single disclosed value
vc.serialize() // back to the wire string

To build a presentation from a parsed credential, use presentSdJwtVc (below).

`presentSdJwtVc(sdJwtVc, holderKeyHex, disclose, binding)`

The per-credential presentation primitive: select disclosures and bind them to the verifier with a key-binding JWT. Synchronous — returns the presentation string.

const presentation = presentSdJwtVc(
  storedCredential.sdJwtVc, // the issued SD-JWT VC string
  holderKeyHex, // seed hex from unwrapHolderKey()
  ['given_name', 'age_over_18'], // claims to disclose
  { aud: verifierOrigin, nonce: verifierNonce }, // bound into the KB-JWT
)

Parameter	Type	Notes
`sdJwtVc`	`string`	The issued SD-JWT VC.
`holderKeyHex`	`string`	Holder seed hex (`KeyPair.toHex()`).
`disclose`	`string[]`	Claim names to reveal.
`binding`	`{ aud: string; nonce: string; iat?: number }`	KB-JWT binding. `iat` defaults to now.

For multi-credential vp_token assembly (OpenID4VP DCQL), use OwlWallet instead.

`verifySdJwt(presentation, issuerPublicKeyHex, requireKb, audience?, nonce?)`

Offline verification of a presentation against a known issuer key. The hosted OwlVerifier.verify() does this plus did:web resolution and revocation checks — use verifySdJwt only for offline / self-contained checks where you already trust the issuer key.

const result = verifySdJwt(presentation, issuerPublicKeyHex, true, verifierOrigin, nonce)
if (result.valid) {
  const claims = JSON.parse(result.claims ?? '{}') // claims is a stringified JSON object
  console.log(claims)
}

Parameter	Type	Notes
`presentation`	`string`	The SD-JWT VC presentation string.
`issuerPublicKeyHex`	`string`	Trusted issuer public key.
`requireKb`	`boolean`	Require a key-binding JWT (`true` for presentations).
`audience`	`string?`	Expected KB-JWT `aud`.
`nonce`	`string?`	Expected KB-JWT `nonce`.

#SD-JWT VC primitives

#KeyPair

#PublicKey

#SdJwtVc