Precompute sign

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

Full example

ECDSA

main.dart

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

const messageHash = 'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

Future<void> preSign(sdk.EcdsaSession session) async {
  // Creating a new keyshare for demo purpose. In real application, you can use an existing keyshare.
  final keyshare = await session.keygen();

  final preSign = await session.preSign(keyshare: keyshare);
  print('Pre computed signature $preSign');

  final signature = await session.finishPreSign(
    messageHash: messageHash,
    preSign: preSign,
  );
  print('Signature: $signature');
}

EdDSA

main.dart

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

const messageHash = 'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

Future<void> preSign(sdk.EddsaSession session) async {
  // Creating a new keyshare for demo purpose. In real application, you can use an existing keyshare.
  final keyshare = await session.keygen();

  final preSign = await session.preSign(keyshare: keyshare);
  print('Pre computed signature $preSign');

  final signature = await session.finishPreSign(
    messageHash: messageHash,
    preSign: preSign,
  );
  print('Signature: $signature');
}

• The preSign method takes an argument.

  • keyshare is the client's "share" of the MPC wallet.

• The preSignature is the precomputed signature(Uint8List) of the message to be signed.

• The finishPresign method takes following argument.

  • preSign is the precomputed signature from the preSign method.
  • messageHash is the hash of the message to be signed as a hex string.

• The signature is the ECDSA(EdDSA) signature (hex string) of messageHash, corresponding to the public key (or address) of the wallet.