Evmos keplr message verifier

Verify messages signed with signArbitrary using evmos addresses

Installation

yarn add @hanchon/evmos-keplr-message-verifier

Usage

Sign a message using keplr

const chainId = 'evmos_9001-2'
const message = 'something'
const address = 'evmos13f4uur7qw3yd87v3ujdle0xtzcjnskywdrnjhp'
const signature = await window.keplr.signArbitrary(
    chainId,
    address,
    message,
)

Verify the message

// Address, message and signature are the same as the previous step
const pubKey = 'A/o4Mu4lzmuWORZPfLfDJIhuFJu2Dwq/ytZBAM1mXNGs'
const validSignature = verifyKeplrSignature(address, pubKey, message, signature)
// if validSignature === true, the message was signed by that address

Note: the pubKey of the current connected address can be obtained using:

await window.keplr.enable(chainId)
const offlineSigner = window.getOfflineSigner(chainId)
const wallets = await offlineSigner.getAccounts()
const pubKey = Buffer.from(wallets[0].pubkey).toString('base64')

Why?

Using keplr to sign with signArbitraty using Evmos it will sign the message using the keccak_256 hashing algorithm, but when validating the message it's using the cosmos' default so it'll return always invalid signer.