@arcadeum/ethauth

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Format

proof = eth.<address>.<claims>.<signature>.<extra>

Address

The account address in hex encoding, ie. '0x9e63b5BF4b31A7F8d5D8b4f54CD361344Eb744C5'.

Note, you should not take the account address in the ethauth proof at face value -- you must parse the Proof and validate it with the library methods provided. The address is included when used to verify smart wallet based accounts (aka contract-based accounts).

Claims

a base64 encoded JSON object of

interface Claims {
  app: string
  iat: number
  exp: number
  n?: number
  typ?: string
  ogn?: string
}

Fields:

• app (required) - App identifier requesting the issuance of the ethauth proof
• iat (required) - Issued at unix timestamp of when the ethauth proof has been signed/issued
• exp (required) - Expired at unix timestamp of when the ethauth proof is valid until
• n (optional) - Nonce value which can be used as a challenge number for added security
• typ (optional) - Type of authorization for this ethauth proof
• ogn (optional) - Domain origin requesting the issuance of the ethauth proof

Signature

Signature value of the claims message payload. The signature is computed by the EIP712 eth_signTypedData call of the claims object. The signature may be recoverable with ECRecover to determine the EOA address, or you may have a different encoding such as one used with EIP-1271, to validate the contract-based account signature.

Example ETHAuth encoding / decoding

EOA account signature

ethauth-proof = eth.0x89d9f8f31817badb5d718cd6fb483b71dbd2dfed.eyJhcHAiOiJFV1RUZXN0IiwiaWF0IjoxNTk1NTMwODQwLCJleHAiOjE1OTU1MzExNDB9.0x233ab9164a677a41acc8d52c9e1d1a621acebf9bc8d956c8474618b589acebe10cc350deb4b02bf6951cec8bd23507170f204ca326a5a264b8f6f67fa2619c251c

decodes & verifies to:

• account address: 0x89D9F8f31817BAdb5D718CD6fb483b71DbD2dfeD
• claims: {"app":"EWTTest","iat":1595530840,"exp":1595531140}
• signature: 0x233ab9164a677a41acc8d52c9e1d1a621acebf9bc8d956c8474618b589acebe10cc350deb4b02bf6951cec8bd23507170f204ca326a5a264b8f6f67fa2619c251c

Contract-based account signature (verifiable with EIP 1271)

ethauth-proof = eth.0x9e63b5bf4b31a7f8d5d8b4f54cd361344eb744c5.eyJpYXQiOjE1OTQ3NDM4NDgsImV4cCI6MTYyNjI3OTg0OCwibiI6MTMzN30.0x000100012dd090aec5e4a9678f7968533c10fc42b07b9a23fa3b719f79a861adcfc7e1d958e3521bb061c34072f5435681390ccc9be19bf9da32320bd2356d0b4b4d316b1c02

decodes & verifies to:

• account address: 0x9e63b5bf4b31a7f8d5d8b4f54cd361344eb744c5
• message: {"iat":1594743848,"exp":1626279848,"n":1337}
• signature: 0x000100012dd090aec5e4a9678f7968533c10fc42b07b9a23fa3b719f79a861adcfc7e1d958e3521bb061c34072f5435681390ccc9be19bf9da32320bd2356d0b4b4d316b1c02

LICENSE

MIT