 Optional features using the parameter block (salting, personalized hashes, tree hashing, et cetera), are not specified, and thus neither is support for BLAKE2bp, BLAKE2sp, or BLAKE2X.BLAKE2b uses an initialization vector that is the same as the IV used by SHA-512.These values are transparently obtained by taking the first 64 bits of the fractional parts of the positive square roots of the first eight prime numbers.