This Node.js extension implements the SHA-3 (Keccak) cryptographic hashing algorithm. It is based on the reference C implementation, version 3.2. The exposed interface is almost identical to that of the crypto standard library. Keccak supports 5 hash lengths: 224-bit, 256-bit, 384-bit, 512-bit and variable length. Variable length is not supported by this Node.js extension. Unless the user specifies otherwise, this Node.js extension assumes 512-bit.