dst_key_frombuffer
dst_key_frombuffer(unsigned int alg, unsigned int flags, unsigned int protocol,
result = dst_key_frombuffer(DST_ALG_HMACSHA1,
result = dst_key_frombuffer(DST_ALG_HMACSHA224,
result = dst_key_frombuffer(DST_ALG_HMACSHA256,
result = dst_key_frombuffer(DST_ALG_HMACSHA384,
result = dst_key_frombuffer(DST_ALG_HMACSHA512,