Blake2b is one of two algorithms based on BLAKE2, the other being Blake2s. Blake2b is optimized for 64-bit platforms, whereas Blake2s is optimized for 8 to 32-bit platforms. It is based on a stream cipher, known as ChaCha, designed by Daniel J. Bernstein. BLAKE2 targets the highest possible security for a hash function. As such, no attack has ever been found on BLAKE2 since its publication in 2012.