BIP32 Support

We support generating signatures for a BIP32 child key. Perform keygen once, and generate signatures for all BIP32 child keys!

Perform Derive Child Public-Key

---

• Call SilentShard.ECDSA.deriveChildPublicKey() or SilentShard.EdDSA.deriveChildPublicKey() which returns Result of Success with Child Public-Key bytes as Data or Failure with error.

Example

---

ECDSA

Example.swift

// deriveChildPublicKey is a stateless helper that takes keyshare bytes, so first
// read the share from your StorageClient by its keyId (the SDK owns keyshare
// storage under the keyId model), then derive the child public key.
func deriveChildPublicKeyUsingKeyId(
        keyId: String, storageClient: CustomStorageClient
) async -> Data? {

    // Read the keyshare addressed by keyId from your own storage.
    guard let dao = try? await storageClient.read(key: keyId),
          let keyshare = dao.currentKeyshare else {
        // no keyshare is stored for this keyId
        return nil
    }

    // Derive the child public key at the desired path.
    let result = await SilentShard.ECDSA.deriveChildPublicKey(
        keyshare,
        derivationPath: "m/1"  // This is an example; use your desired path, e.g. "m/1/2"
    )
    // returns nil if operation fails or other flow you might have
    switch result {
    case .success(let childPublicKey):
        // do something with the derived child public key bytes
        Swift.print(childPublicKey)
        return childPublicKey
    case .failure(let error):
        // show error to user or abort process
        Swift.print(error)
        return nil
    }
}

EdDSA

Example.swift

// deriveChildPublicKey is a stateless helper that takes keyshare bytes, so first
// read the share from your StorageClient by its keyId (the SDK owns keyshare
// storage under the keyId model), then derive the child public key.
func deriveChildPublicKeyUsingKeyId(
        keyId: String, storageClient: CustomStorageClient
) async -> Data? {

    // Read the keyshare addressed by keyId from your own storage.
    guard let dao = try? await storageClient.read(key: keyId),
          let keyshare = dao.currentKeyshare else {
        // no keyshare is stored for this keyId
        return nil
    }

    // Derive the child public key at the desired path.
    let result = await SilentShard.EdDSA.deriveChildPublicKey(
        keyshare,
        derivationPath: "m/1"  // This is an example; use your desired path, e.g. "m/1/2"
    )
    // returns nil if operation fails or other flow you might have
    switch result {
    case .success(let childPublicKey):
        // do something with the derived child public key bytes
        Swift.print(childPublicKey)
        return childPublicKey
    case .failure(let error):
        // show error to user or abort process
        Swift.print(error)
        return nil
    }
}

• When duoSession.sign() is called with a derivationPath, the signature is generated for the specified BIP32 derivation path.
• derivationPath is a string that specifies the path to the child key. It defaults to 'm' (no derivation) if not provided.