feat: support starknet multiple signers signature

[wa0x6e]

Toward snapshot-labs/sx-monorepo#1585

This PR adds support for verifying starknet messages signed by multiple signers.

This will enable verifying messages signed by argent x smart account wallets, with argent shield enabled (https://docs.ready.co/aa-use-cases/verifying-signatures-and-cosigners#verifying-multi-signatures)

Also adding a new hashtype for the new starknet alias payload, which is now following the SNIP-12 format (https://github.com/starknet-io/SNIPs/blob/main/SNIPS/snip-12.md)

{
  StarkNetDomain: [
    { name: 'name', type: 'felt' },
    { name: 'version', type: 'felt' },
    { name: 'chainId', type: 'felt' }
  ],
  SetAlias: [
    { name: 'from', type: 'felt' },
    { name: 'alias', type: 'felt' },
    { name: 'timestamp', type: 'felt' }
  ]
}

How to test

• Use this branch: feat: migrate offchain starknet signing to support SNIP-12 sx-monorepo#1588
• Connect with an argent X smart account wallet
• Create an alias (follow a space)
• Sign the message
• In the dev console, network tab, copy and send the sign payload to the starknet verify function (the sig array first element should be 0x2)
• It should return true
• Repeat with a standard wallet
• It should also work
• Repeat using the master branch
• It should also work (does not break existing feature)

Note

We're only supporting SNIP-12 revision 0

Revision 1 require starknet.js v7, which require node >= 22

[Copilot]

Pull Request Overview

This PR adds support for verifying Starknet messages signed by multiple signers, enabling verification of Argent X smart account wallets with Argent Shield. It introduces a new signature parsing function and updates the verification logic to handle multi-signer scenarios while maintaining backward compatibility.

Key changes:

• Implements multi-signer signature verification for Starknet
• Adds new hash type for SNIP-12 format alias payload
• Maintains backward compatibility with existing single-signer verification

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/verify/starknet.ts	Adds getSignatureArray function and updates verify logic to handle multi-signer signatures
src/verify/starknet.spec.ts	Adds test coverage for multi-signer verification scenarios
test/fixtures/starknet/message-alias-multisigner.json	New test fixture for multi-signer signature verification
src/sign/hashedTypes.json	Adds new hash type for SNIP-12 format alias payload

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[ChaituVR]

why it will return true for different network 🤔

[wa0x6e]

This is the old behavior.

It's just highlighting that the behavior is different when there is a co-signer

[ChaituVR]

Is it because normal signatures doesn't depend on network?

[wa0x6e]

verification always occur onchain, by calling a contract method. it's weird that it works

[ChaituVR]

tAck