Keccak Algorithm | cryptocurrencies, blockchains & live prices

Keccak is a cryptographic hash function based on the sponge construction, a fundamentally different design from the Merkle-Damgård structure used by SHA-1 and SHA-2. Developed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche, Keccak operates by absorbing input data into a fixed-size internal state through XOR operations and then squeezing out the hash output. The internal state consists of a 1600-bit array organized as a 5x5 matrix of 64-bit words, which is repeatedly transformed using a permutation function called Keccak-f consisting of 24 rounds of five operations: theta, rho, pi, chi, and iota.

Keccak provides excellent security properties with a clean mathematical foundation. Its sponge construction offers inherent protection against length extension attacks, a vulnerability that affects SHA-2 and requires workarounds like HMAC. The algorithm supports variable-length output, making it highly versatile for different security requirements. In terms of performance, Keccak is efficient on a wide range of platforms from embedded devices to high-performance servers, and its simple bitwise operations make it well-suited for hardware implementation. The extensive cryptanalysis performed during the SHA-3 competition confirmed its large security margins.

Keccak won the NIST hash function competition in 2012 after a rigorous five-year selection process involving 64 initial submissions, ultimately being standardized as SHA-3 in 2015. In the cryptocurrency space, Keccak is used as a mining algorithm by several projects, most notably Maxcoin and 365Coin. It is also the hash function underlying Ethereum's internal operations — Ethereum uses Keccak-256 extensively for address derivation, transaction hashing, and Merkle tree construction, though it uses Ethash (now replaced by proof-of-stake) rather than raw Keccak for consensus. The algorithm's influence extends far beyond mining, serving as a foundational building block in numerous blockchain protocols and cryptographic systems.