;
};
Sui has [native multisig](https://docs.sui.io/concepts/cryptography/transaction-auth/multisig) support: a k-of-n set of members, each with a weight, that together produce one combined signature once the participating members' weights reach a threshold. Para's Sui integration lets a Para MPC wallet be one member of a multisig.
## How it works
A Sui multisig is fully defined by its **members** (each a public key + `weight`) and a **`threshold`**. Deriving its address is a pure, offline operation. Signing is a three-step flow:
1. Each participating member signs the **same** transaction or message bytes independently, producing a *partial* signature.
2. The partials are **combined** into a single multisig signature.
3. The combined signature is submitted alongside the transaction bytes (or verified off-chain).
Multisigs are k-of-n with up to 10 members, per-member `weight` (1–255), and a `threshold` (the summed weight required). The multisig has its own address, distinct from any member's.
## With the hook
[`useParaSuiMultiSigSigner`](/v3/react/guides/hooks/use-para-sui-multisig-signer) returns a signer that bundles the whole flow. Pass the co-signers as `otherMembers`; the Para member is added automatically.
```tsx theme={null}
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 ;
}
```
For a transaction, use `multiSigSigner.signTransaction(bytes)` / `verifyTransaction`, and set the transaction's `sender` to `multiSigSigner.address`.
## With the helper functions
The same flow is available as framework-agnostic functions from `@getpara/sui-sdk-integration`, for non-React code or when you only have some members locally:
```typescript theme={null}
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] });
```
Only signatures from members whose combined weight meets the `threshold` are required, and the order does not matter. `createParaSuiMultiSigSigner` (used by the hook) accepts either a `paraSigner` from `useParaSuiSigner` or a `para` instance directly.
## Reference
