Authorizations
x402 blockchain payment authorization header containing signed EIP-3009 Transfer with Authorization
Compute the Keccak-256 (SHA3) hash of arbitrary input data. Returns the hash as a hex string. Essential for Ethereum signature verification, contract function selectors, and cryptographic operations. Commonly used for generating method signatures and data integrity checks. Requires x402 blockchain payment.
x402 blockchain payment authorization header containing signed EIP-3009 Transfer with Authorization