Wallet Signatures

Before You Start

Read the following guides before proceeding:

Overview

Some corporate operations require the employee to sign a sentence with their wallet. Each operation's page
gives its sentence and its errors. This page covers what they share: who signs and how each wallet type
encodes the signature.

Transaction authorization — the mode, the transaction_authorization object, nonce and reuse rules, and
its errors — is described once in Transaction Authorization.

Estimates, confirmations, reads, card management and bulk transfers take no signature. A bulk transfer is
signed on-chain.

Who Signs

The signer is always the wallet in the corporation token's employee_address claim — the X-User-Wallet
sent to POST /api/v1/corporations/login.

• An employee signs with their own wallet. The corporation owner's signature does not authorize an
  employee's request, even over the same sentence.
• A smart account is a different signer from the EOA that controls it. If the employee logged in with
  an EOA, the EOA signs. ERC-1271 applies only when employee_address itself is the contract.

Encoding by Wallet Type

The sentence is signed character for character. Any difference — case, spacing, a different id or nonce —
produces a signature that is rejected.

Smart-Contract Wallets

• The contract must be deployed on the chain in the corporation token's chain_id claim — the
  X-Chain-Id sent at login, or the default chain when none was sent. An undeployed (counterfactual)
  account cannot sign.
• Wirex calls isValidSignature only when the signature does not recover to employee_address as an EOA
  signature, so an EOA signature never depends on a node call.
• The call has a 3-second timeout. A timeout, a revert, an unreachable node or any return value other than
  0x1626ba7e rejects the signature.

Signing the Sentence

The examples sign with an EOA key (EIP-191). With an embedded or browser wallet, pass the same sentence to
its personal_sign / signMessage.

import { privateKeyToAccount } from 'viem/accounts';

const account = privateKeyToAccount(employeePrivateKey); // the employee_address wallet
const signature = await account.signMessage({ message: sentence }); // 0x…, 65 bytes

from eth_account import Account
from eth_account.messages import encode_defunct

signature = Account.sign_message(encode_defunct(text=sentence), employee_private_key).signature.hex()
if not signature.startswith("0x"):
    signature = "0x" + signature

sig, _ := crypto.Sign(accounts.TextHash([]byte(sentence)), employeeKey)
sig[crypto.RecoveryIDOffset] += 27
signature := hexutil.Encode(sig)