Platform

BIP32 Support

Please refer to the Session creation section to learn how to create a new session.

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

Full example:

ECDSA
EdDSA

App.tsx
import { type EcdsaSession } from '@silencelaboratories/silent-shard-sdk/ecdsa';

const messageHash = 'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

// We will MPC functions here
export const keyDerivation = async (session: EcdsaSession) => {
  // Keygen
  const keyshare = await session.keygen();
  console.log('Generated keyshare: ', keyshare.keyIdHex);
  const signConfig = {
    keyshare,
    messageHash,
    derivationPath: 'm', // This is the default, use your desired path here. For e.g., 'm/1/2'
  };
  const signature = await session.sign(signConfig);
  console.log('Signature:', signature);
  // Get public key of newly generated wallet
  const publicKey = keyshare.publicKeyHex;
  console.log('Public key:', publicKey);

  // Derive a child public key from keyshare
  const derivedPublicKey = await keyshare.deriveChildPublicKey('m');
  console.log('Derived public key:', derivedPublicKey);
};

App.tsx
import { type EddsaSession } from '@silencelaboratories/silent-shard-sdk/eddsa';

const messageHash = 'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

// We will MPC functions here
export const keyDerivation = async (session: EddsaSession) => {
  // Keygen
  const keyshare = await session.keygen();
  console.log('Generated keyshare: ', keyshare.keyIdHex);
  const signConfig = {
    keyshare,
    messageHash,
    derivationPath: 'm', // This is the default, use your desired path here. For e.g., 'm/1/2'
  };
  const signature = await session.sign(signConfig);
  console.log('Signature:', signature);
  // Get public key of newly generated wallet
  const publicKey = keyshare.publicKeyHex;
  console.log('Public key:', publicKey);

  // Derive a child public key from keyshare
  const derivedPublicKey = await keyshare.deriveChildPublicKey('m');
  console.log('Derived public key:', derivedPublicKey);
};

When session.sign(signConfig)(EcdsaSignConfig) 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.

Please refer to the Session creation section to learn how to create a new session.

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

Full example:

ECDSA
EdDSA
Taproot

main.dart
import 'package:silent_shard_sdk/silent_shard_sdk.dart' as sdk;

const messageHash =
    'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

Future<void> keyDerivation(sdk.EcdsaSession session) async {
  // Keygen
  final sdk.DklsKeyshare keyshare = await session.keygen();
  print('Keyshare created, public key: ${keyshare.publicKeyHex}');

  final signature = await session.sign(
    keyId: keyshare.keyId,
    messageHash: messageHash,
    derivationPath:
        'm', // This is the default, use your desired path here. For e.g 'm/1/2'
  );
  print('Signature: $signature');

  final publicKey = keyshare.publicKeyHex;
  print('Public key: $publicKey');

  final derivedPublicKey = keyshare.deriveChildPublicKeyHex('m');
  print('Derived public key: $derivedPublicKey');
}

main.dart
import 'package:silent_shard_sdk/silent_shard_sdk.dart' as sdk;

const messageHash =
    'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

Future<void> keyDerivation(sdk.EddsaSession session) async {
  // Keygen
  final sdk.SchnorrKeyshare keyshare = await session.keygen();
  print('Keyshare created, public key: ${keyshare.publicKeyHex}');

  final signature = await session.sign(
    keyId: await keyshare.keyId,
    messageHash: messageHash,
    derivationPath:
        'm', // This is the default, use your desired path here. For e.g 'm/1/2'
  );
  print('Signature: $signature');

  final publicKey = keyshare.publicKeyHex;
  print('Public key: $publicKey');

  final derivedPublicKey = keyshare.deriveChildPublicKeyHex('m');
  print('Derived public key: $derivedPublicKey');
}

main.dart
import 'package:silent_shard_sdk/silent_shard_sdk.dart' as sdk;

const messageHash =
    'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

Future<void> keyDerivation(sdk.TaprootSession session) async {
  // Keygen
  final sdk.TaprootKeyshare keyshare = await session.keygen();
  print('Keyshare created, public key: ${keyshare.publicKeyHex}');

  final signature = await session.sign(
    keyId: keyshare.keyId,
    messageHash: messageHash,
  );
  print('Signature: $signature');

  final derivedPublicKey = keyshare.deriveChildPublicKeyHex('m/86/0/0/0/0');
  print('Derived public key: $derivedPublicKey');
}

When session.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.

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 ByteArray or Failure with exception.

Example

ECDSA
EdDSA

Example.kt

suspend fun deriveChildPublicKeyUsingKeyshare(
    keyId: String,
    trioSession: TrioSession,
    storageClient: StorageClient,
): ByteArray {
    return withContext(Dispatchers.IO) {
        //signature example for context
        trioSession.sign(
            keyId = keyId,
            message = messageHash,
            derivationPath = "m" // This is the default, use your desired path here. For e.g. 'm/1/2'
        ).getOrThrow()


        // Read the keyshare bytes from your StorageClient by keyId.
        val keyshare = (storageClient.read(keyId) as ReconcileStoreDao).currentKeyshare!!

        // child public key derivation
        SilentShard.ECDSA.deriveChildPublicKey(
            keyshare = keyshare,
            derivationPath = "m/1"
        ).getOrThrow()
    }
}

Example.kt

suspend fun deriveChildPublicKeyUsingKeyshare(
    keyId: String,
    trioSession: TrioSession,
    storageClient: StorageClient,
): ByteArray {
    return withContext(Dispatchers.IO) {
        //signature example for context
        trioSession.sign(
            keyId = keyId,
            message = messageHash,
            derivationPath = "m" // This is the default, use your desired path here. For e.g. 'm/1/2'
        ).getOrThrow()


        // Read the keyshare bytes from your StorageClient by keyId.
        val keyshare = (storageClient.read(keyId) as ReconcileStoreDao).currentKeyshare!!

        // child public key derivation
        SilentShard.EdDSA.deriveChildPublicKey(
            keyshare = keyshare,
            derivationPath = "m/1"
        ).getOrThrow()
    }
}

When trioSession.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.

The derivation above computes a child public key from your existing key. For ECDSA sessions, hardDerivation(keyId, derivationPath) performs an MPC hardened derivation and returns a new child keyId that you can sign with directly.

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
EdDSA

Example.swift
// deriveChildPublicKey computes a child public key locally, without any MPC round.
// It takes keyshare bytes, which you read from your own StorageClient by keyId
// (the SDK owns keyshare storage). This is a public-key-only derivation — for a
// signable child keyshare use trioSession.hardDerivation(keyId:derivationPath:).
func deriveChildPublicKey(keyshare: Data) async -> Data? {
    let result = await SilentShard.ECDSA.deriveChildPublicKey(
        keyshare,
        derivationPath: "m/1"  // your desired BIP32 path
    )
    // returns nil if the operation fails, or handle it however your flow needs
    switch result {
    case .success(let childPublicKey):
        // do something with the child public-key bytes
        Swift.print(childPublicKey)
        return childPublicKey
    case .failure(let error):
        // show the error to the user or abort the process
        Swift.print(error)
        return nil
    }
}

Example.swift
// deriveChildPublicKey computes a child public key locally, without any MPC round.
// It takes keyshare bytes, which you read from your own StorageClient by keyId
// (the SDK owns keyshare storage).
func deriveChildPublicKey(keyshare: Data) async -> Data? {
    let result = await SilentShard.EdDSA.deriveChildPublicKey(
        keyshare,
        derivationPath: "m/1"  // your desired BIP32 path
    )
    // returns nil if the operation fails, or handle it however your flow needs
    switch result {
    case .success(let childPublicKey):
        // do something with the child public-key bytes
        Swift.print(childPublicKey)
        return childPublicKey
    case .failure(let error):
        // show the error to the user or abort the process
        Swift.print(error)
        return nil
    }
}

When trioSession.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.