@zk-email/jwt-tx-builder-circuits

The circuits package exports the circom circuits needed for building on jwt-tx-builder.

All circuits in this package are libraries that can be imported to your circom project (i.e this package does not contain a main circuit).

Installation

yarn add @zk-email/jwt-tx-builder-circuits

JWT Auth Circuit

The JWT Auth circuit is the core circuit for verifying JWT signatures and actions using the JWT Auth protocol.

Usage

Import to your circuit file like below.

include "@zk-email/jwt-tx-builder-circuits/jwt-auth.circom";

• Parameters:
  • n: Number of bits per chunk the RSA key is split into. Recommended to be 121.
  • k: Number of chunks the RSA key is split into. Recommended to be 17.
  • maxMessageLength: Maximum length of the JWT message (header + payload).
  • maxB64HeaderLength: Maximum length of the base64 encoded header.
  • maxB64PayloadLength: Maximum length of the base64 encoded payload.
  • maxAzpLength: Maximum length of the "azp" (authorized party) claim.
  • maxCommandLength: Maximum length of the "command" claim.

Note: We use these values for n and k because their product (n * k) needs to be more than 2048 (RSA constraint) and n has to be less than half of 255 to fit in a circom signal.

• Inputs:

  • message: The JWT message (header + payload).
  • messageLength: Actual length of the message signed in the JWT.
  • pubkey: The RSA public key split into k chunks of n bits each.
  • signature: The RSA signature split into k chunks of n bits each.
  • accountCode: The account code. (Used in the context of a jwt-wallet to identify the smart wallet)
  • codeIndex: The index of the "account code" in the "command".
  • periodIndex: The index of the period in the JWT message.
  • jwtKidStartIndex: The index of the "kid" in the JWT header.
  • issKeyStartIndex: The index of the "iss" key in the JWT payload.
  • issLength: The length of the "iss" claim in the JWT payload.
  • iatKeyStartIndex: The index of the "iat" key in the JWT payload.
  • azpKeyStartIndex: The index of the "azp" (authorized party) key in the JWT payload.
  • azpLength: The length of the "azp" (authorized party) claim in the JWT payload.
  • emailKeyStartIndex: The index of the "email" key in the JWT payload.
  • emailLength: The length of the "email" claim in the JWT payload.
  • nonceKeyStartIndex: The index of the "nonce" key in the JWT payload.
  • commandLength: The length of the "command" claim in the "nonce" key in the JWT payload.
  • emailDomainIndex: The index of the domain in the email.
  • emailDomainLength: The length of the domain in the email.

• Outputs:

  • kid: The "kid" (key ID) claim in the JWT header.
  • iss: The "iss" (issuer) claim in the JWT payload.
  • publicKeyHash: The SHA256 hash of the RSA public key.
  • jwtNullifier: The unique nullifier for the JWT.
  • timestamp: The "iat" (issued at) claim in the JWT payload.
  • maskedCommand: The "command" claim in the JWT payload with the "accountCode" masked and receiving email address masked.
  • accountSalt: The "accountSalt" claim in the JWT payload.
  • azp: The "azp" (authorized party) claim in the JWT payload.
  • domainName: The domain name extracted from the email.
  • isCodeExist: Whether the "accountCode" exists in the "command" claim.