* @brief blake2b hash function * * This is the front-end function that sets up the argument for BLAKE2B(). * * @param message the message to be hashed * @param len length of message (0 <= len < 2**128) (depends on sizeof(size_t) * for this implementation) * @param key optional secret key * @param kk length of optional secret key (0 <= kk <= 64) * @param nn length of output digest (1 <= nn