tz-wallet-sdk

Tezos/DMV domain logic for the SpruceId wallet-binding feature. Per OID4VP presentation a self-signed TezosWalletBindingCredential is minted — a jwt_vc_json verifiable credential (compact JWS) that proves the holder controls an independent Tezos key.

The wire format is defined by the wallet-binding contract (dev/wallet-binding/CONTRACT.md); the verifier counterpart lives in vdc-portal (src/verifier/wallet_binding.rs). This repo mints exactly what that verifier consumes.

Workspace layout

This is a Cargo workspace of three crates:

Crate	Role	SDK-coupled?
crates/tezos-address	Derive Tezos implicit addresses (tz1/tz2/tz3) from public keys	no (blake2, bs58)
crates/tezos-wallet-binding	Core schema + mint_binding_jws + binding_query_match	no (signer-agnostic)
crates/tezos-wallet-binding-provider	SDK DynamicCredentialProvider over the core	yes (mobile-sdk-rs)

The split keeps the mint/wire logic (tezos-wallet-binding) free of any mobile-sdk-rs dependency: it is unit-testable on its own and re-exports the tezos-address derivation. Only tezos-wallet-binding-provider pulls the SDK.

tezos-wallet-binding (core, SDK-free)

// Pure, signer-agnostic mint. Returns the compact JWS.
pub fn mint_binding_jws<E, F>(
    public_jwk_json: &str,
    nonce: &str,
    client_id: &str,
    sign: F,
) -> Result<String, MintError>
where
    E: std::fmt::Display,
    F: FnOnce(&[u8]) -> Result<Vec<u8>, E>;

// Returns Some(credential_query_id) iff a DCQL credential query targets the
// TezosWalletBindingCredential type (format jwt_vc_json + meta.type_values).
pub fn binding_query_match(query_json: &str) -> Option<String>;

// Schema constants: VC_CONTEXT, VC_TYPE, BINDING_CREDENTIAL_TYPE,
// BINDING_METHOD, BINDING_FORMAT, OFFER_ID, OFFER_TITLE.
// Error type: MintError.
// Re-exports: `pub use tezos_address;` plus tz1_from_ed25519,
// tz3_from_p256_coords, tz3_from_p256_compressed, tz2_from_secp256k1_compressed.

ES256 signatures are normalized to RFC 7515 raw 64-byte r||s with p256 directly (parse Signature::from_slice or from_der, re-emit to_bytes()) — this replaces the previous mobile_sdk_rs::crypto::CryptoCurveUtils call and is byte-identical to it. EdDSA signatures are already raw 64-byte and pass through.

tezos-wallet-binding-provider (SDK-coupled)

// SDK DynamicCredentialProvider over an app-supplied Tezos SigningKey.
pub struct TezosWalletBindingProvider { /* private */ }
impl TezosWalletBindingProvider {
    pub fn new(signing_key: Arc<dyn mobile_sdk_rs::crypto::SigningKey>) -> Self;
}
impl mobile_sdk_rs::oid4vp::dynamic_credential::DynamicCredentialProvider
    for TezosWalletBindingProvider { /* offers + mint */ }

Supported keys

JWK	alg	tz address
OKP / Ed25519	EdDSA	tz1...
EC / P-256	ES256	tz3...

Dependencies

tezos-address and tezos-wallet-binding are path deps within the workspace. The provider depends on mobile-sdk-rs via a git pin: spruceid/sprucekit-mobile branch feat/dynamic-credential-provider (PR #314).