The signing module provides utilities for signing CoW Protocol orders using various signature schemes.
Types
SigningScheme
Enum representing the signature scheme used to sign an order.
enum SigningScheme {
EIP712 = 0b00,
ETHSIGN = 0b01,
EIP1271 = 0b10,
PRESIGN = 0b11
}
EIP-712 typed data signing (preferred). Provides more information to wallets about the data being signed.
Message signed using eth_sign RPC call.
Smart contract signatures as defined in EIP-1271. For contract-based wallets.
Pre-signed order. The order is signed on-chain before submission.
Signature
Union type representing any valid order signature.
type Signature = EcdsaSignature | Eip1271Signature | PreSignSignature;
EcdsaSignature
ECDSA signature for EIP-712 or ETHSIGN schemes.
interface EcdsaSignature {
scheme: EcdsaSigningScheme;
data: SignatureLike;
}
scheme
SigningScheme.EIP712 | SigningScheme.ETHSIGN
required
The ECDSA signing scheme used.
The ECDSA signature data (r, s, v components).
Eip1271Signature
EIP-1271 smart contract signature.
interface Eip1271Signature {
scheme: SigningScheme.EIP1271;
data: Eip1271SignatureData;
}
scheme
SigningScheme.EIP1271
required
Must be SigningScheme.EIP1271.
data
Eip1271SignatureData
required
The EIP-1271 signature data containing verifier and signature bytes.
Eip1271SignatureData
Data for EIP-1271 signature verification.
interface Eip1271SignatureData {
verifier: string;
signature: BytesLike;
}
The address of the smart contract that will verify the signature.
Arbitrary signature data passed to the verifying contract’s isValidSignature method.
PreSignSignature
Signature data for a pre-signed order.
interface PreSignSignature {
scheme: SigningScheme.PRESIGN;
data: string;
}
scheme
SigningScheme.PRESIGN
required
Must be SigningScheme.PRESIGN.
The address of the order signer.
Functions
signOrder
Signs a CoW Protocol order using an externally owned account (EOA).
async function signOrder(
domain: TypedDataDomain,
order: Order,
owner: Signer,
scheme: EcdsaSigningScheme
): Promise<EcdsaSignature>
The EIP-712 domain separator. Ensures orders can’t be replayed across different deployments or chains.
The Ethers.js signer (wallet) that will sign the order.
scheme
EcdsaSigningScheme
required
The signing scheme to use: SigningScheme.EIP712 (recommended) or SigningScheme.ETHSIGN.
The ECDSA signature with the signing scheme encoded.
Example
import { signOrder, SigningScheme, domain } from "@cowprotocol/contracts";
import { Wallet } from "ethers";
const wallet = new Wallet("0x...");
const settlementDomain = domain(1, "0x9008D19f58AAbD9eD0D60971565AA8510560ab41");
const signature = await signOrder(
settlementDomain,
order,
wallet,
SigningScheme.EIP712
);
encodeEip1271SignatureData
Encodes EIP-1271 signature data for use with CoW Protocol contracts.
function encodeEip1271SignatureData(
data: Eip1271SignatureData
): string
data
Eip1271SignatureData
required
The EIP-1271 signature data to encode.
Hex-encoded signature data with verifier address and signature bytes packed together.
decodeEip1271SignatureData
Decodes a CoW Protocol EIP-1271 signature into its components.
function decodeEip1271SignatureData(
signature: BytesLike
): Eip1271SignatureData
The encoded EIP-1271 signature data.
The decoded signature containing the verifier address and signature bytes.
Constants
EIP1271_MAGICVALUE
The magic value returned by a successful isValidSignature call.
const EIP1271_MAGICVALUE = "0x1626ba7e";
This is bytes4(keccak256("isValidSignature(bytes32,bytes)")) as defined in the EIP-1271 standard.
Usage Notes
EIP-712 is the recommended signing scheme as it provides the best user experience. Wallets can display structured information about what the user is signing.
EIP-1271 is required for smart contract wallets like Gnosis Safe, Argent, or any contract-based wallet that doesn’t have a private key.
Pre-signed orders require an on-chain transaction to authorize the order before it can be settled. This is useful for integration with other smart contracts.
Type Definitions
SignatureLike
A type that can be converted to an Ethers.js signature.
type SignatureLike = string | {
r: string;
s: string;
v: number;
yParityAndS?: string;
compact?: string;
};
EcdsaSigningScheme
Type alias for ECDSA signing schemes.
type EcdsaSigningScheme = SigningScheme.EIP712 | SigningScheme.ETHSIGN;
Complete Example
import {
Order,
OrderKind,
signOrder,
SigningScheme,
domain,
Signature,
} from "@cowprotocol/contracts";
import { Wallet } from "ethers";
// Create an order
const order: Order = {
sellToken: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
buyToken: "0x6B175474E89094C44Da98b954EedeAC495271d0F",
sellAmount: "1000000000000000000",
buyAmount: "3000000000000000000000",
validTo: Math.floor(Date.now() / 1000) + 3600,
appData: 1,
feeAmount: "5000000000000000",
kind: OrderKind.SELL,
partiallyFillable: false,
};
// Sign the order
const wallet = new Wallet(privateKey);
const settlementDomain = domain(1, "0x9008D19f58AAbD9eD0D60971565AA8510560ab41");
const signature: Signature = await signOrder(
settlementDomain,
order,
wallet,
SigningScheme.EIP712
);
console.log("Signature scheme:", signature.scheme);
console.log("Signature data:", signature.data);
