Keccak

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Keccak is a cryptographic hash function submitted to the NIST hash function competition by Guido Bertoni, Joan Daemen, Michaël Peeters and Gilles Van Assche. The authors claim 12.5 cycles per byte on an Intel Core 2 CPU. Keccak uses the sponge construction in which message blocks are XORred into the initial bits of the state, which is then invertibly permuted. A cryptographic hash function is a deterministic procedure that takes an arbitrary block of data and returns a fixed-size bit string, the (cryptographic) hash value, such that an accidental or intentional change to the data will change the hash value. The data to be encoded is often called the "message", and the hash value is sometimes called the message digest or simply digest.