Sui Multisig with Para

import { useMemo } from "react";
import { useParaSuiMultiSigSigner } from "@getpara/react-sdk";
import { Ed25519Keypair } from "@mysten/sui/keypairs/ed25519";

function ParaMultiSig() {
  const coSigner = useMemo(() => new Ed25519Keypair(), []);

  const { multiSigSigner } = useParaSuiMultiSigSigner({
    otherMembers: [{ publicKey: coSigner.getPublicKey(), weight: 1 }],
    threshold: 2,
  });

  const sign = async () => {
    if (!multiSigSigner) return;

    const msg = new TextEncoder().encode("gm from a Para multisig");

    // Each member signs the same bytes independently.
    const { signature: paraPartial } = await multiSigSigner.signPersonalMessage(msg);
    const { signature: coPartial } = await coSigner.signPersonalMessage(msg);

    // Combine, then verify or submit.
    const combined = multiSigSigner.combine([paraPartial, coPartial]);
    const ok = await multiSigSigner.verifyPersonalMessage(msg, combined);

    console.log("Multisig address:", multiSigSigner.address);
    console.log("Valid:", ok);
  };

  return <button onClick={sign}>Sign with multisig</button>;
}

import { useClient } from "@getpara/react-sdk";
import {
  getParaSuiMultiSigMember,
  getSuiMultiSigAddress,
  combineSuiMultiSigSignatures,
  signSuiMultiSigTransactionWithPara,
} from "@getpara/sui-sdk-integration";
import { Ed25519Keypair } from "@mysten/sui/keypairs/ed25519";

const para = useClient();
const coSigner = new Ed25519Keypair();

// Members: the Para wallet (weight 1) + a co-signer (weight 1), 2-of-2.
const members = [
  getParaSuiMultiSigMember({ para, weight: 1 }),
  { publicKey: coSigner.getPublicKey(), weight: 1 },
];
const threshold = 2;

// The multisig address (offline).
const address = getSuiMultiSigAddress({ members, threshold });

// Each member signs the transaction bytes, then combine.
const paraPartial = await signSuiMultiSigTransactionWithPara({ para, transactionBytes });
const { signature: coPartial } = await coSigner.signTransaction(transactionBytes);
const combined = combineSuiMultiSigSignatures({ members, threshold, signatures: [paraPartial, coPartial] });