keccak256 top-level constant
Keccak-256 is a member of Keccak family hash functions that generates a 256-bit hash.
Keccak is a secure and versatile hash function family that uses a simple sponge construction and Keccak-f cryptographic permutation. After its selection as the winner of the SHA-3 competition, Keccak has been standardized in NIST standards FIPS 202
Note that the standard implementation of Keccak-256 is available as SHA3-256. This one follows the original design. However, the only difference between them is the choice of the final padding.
Implementation
const BlockHashBase keccak256 = _Keccak256();