@zk-email/contracts v6.0.3

Set up

yarn install

DKIMRegistry.sol

The DKIMRegistry.sol is a Solidity contract that serves as a registry for storing the hash of the DomainKeys Identified Mail (DKIM) public key for each domain. This contract is part of the @zk-email/contracts package.

Overview

The DKIMRegistry contract maintains a record of the DKIM key hashes for public domains. The hash is calculated by taking the Poseidon hash of the DKIM key split into 9 chunks of 242 bits each.

The contract provides methods to set and revoke DKIM public key hashes, and to check if a DKIM public key hash is valid. The contract also emits events when a DKIM public key hash is registered or revoked.

Key Features

• DKIM Public Key Hash Registration: The setDKIMPublicKeyHash function allows the contract owner to register a new DKIM public key hash for a domain. The function emits a DKIMPublicKeyHashRegistered event upon successful registration.

• DKIM Public Key Hash Revocation: The revokeDKIMPublicKeyHash function allows the contract owner to revoke a DKIM public key hash. The function emits a DKIMPublicKeyHashRevoked event upon successful revocation.

• DKIM Public Key Hash Validation: The isDKIMPublicKeyHashValid function checks if a DKIM public key hash is valid for a given domain. It returns false if the hash has been revoked or if it does not exist for the domain.

• Batch DKIM Public Key Hash Registration: The setDKIMPublicKeyHashes function allows the contract owner to register multiple DKIM public key hashes for a domain at once.

Security

The contract extends the Ownable contract from the OpenZeppelin contracts library, which provides basic access control mechanisms. Only the contract owner can register or revoke DKIM public key hashes.

Usage

The DKIMRegistry contract is used in conjunction with the EmailVerifier circuit to verify emails. The EmailVerifier circuit checks the DKIM signature of an email against the DKIM public key hash stored in the DKIMRegistry contract for the email's domain.

For a more in-depth understanding, please visit our zk Email Verify repository at https://github.com/zkemail/zk-email-verify.