Platform

Sign

Produce a signature over a message hash. The device and the Duo Server each sign with their own share, and the results combine into a single, standard signature. The full private key is never reassembled.

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

Full example

ECDSA

App.tsx

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

// This could be a hash digest of any message you want to sign.
// For example, for the Ethereum transaction signing, you would use the keccak256 hash of the transaction data.
const messageHash = 'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

export const signGen = async (session: EcdsaSession) => {
  // Creating a new keyshare for demo purpose. In real application, you can use an existing keyshare.
  const keyshare = await session.keygen();

  const signConfig = {
    keyshare,
    messageHash,
  };
  const signature = await session.sign(signConfig);

  console.log('Signature:', signature);
};

EdDSA

App.tsx

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

const messageHash = 'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

export const signGen = async (session: EddsaSession) => {
  // Creating a new keyshare for demo purpose. In real application, you can use an existing keyshare.
  const keyshare = await session.keygen();

  const signConfig = {
    keyshare,
    messageHash,
  };
  const signature = await session.sign(signConfig);

  console.log('Signature:', signature);
};

MLDSA

App.tsx

import { MldsaLevels } from '@silencelaboratories/silent-shard-sdk';
import { type MldsaSession } from '@silencelaboratories/silent-shard-sdk/mldsa';

const messageHash = 'e2a159d17b7bb714aed7675d7c7d394dec8d2e4337842848104694bf89c71c03';

export const signGen = async (session: MldsaSession) => {
  // Creating a new keyshare for demo purpose. In real application, you can use an existing keyshare.
  const keyshare = await session.keygen();

  const signConfig = {
    keyshare,
    messageHash,
    // ML-DSA security level (MlDsa44, MlDsa65, or MlDsa87)
    level: MldsaLevels.MlDsa44,
  };
  const signature = await session.sign(signConfig);

  console.log('Signature:', signature);
};

• The sign method takes a EcdsaSignConfig object as an argument.
• keyshare(Keyshare) is the client's "share" of the MPC wallet.
• messageHash is the hash of the message to be signed as a hex string.
• When session.sign() is called, the app and the server exchange messages to generate an ECDSA signature.
• signature is the ECDSA signature (hex string) of messageHash, corresponding to the public key (or address) of the wallet.

Handling the operation

This is an MPC operation, so it takes a few seconds (the app and the Duo Server exchange several messages). Show a non-blocking loading state while it runs, confirm on success, and offer a retry on failure. When something goes wrong, the SDK surfaces the error for you to handle:

Error	What it means	How to handle
Keyshares not in sync, run reconcile	A previous operation didn't finish cleanly (for example the app was force-closed mid-operation)	Run reconcile, then retry
Server error	The server ended the session unexpectedly	Show the error and offer a retry
Connection / transport error	The server was unreachable or the connection dropped	Show the error and offer a retry

All of these operations are safe to retry from the start.