HMAC actually double-hashes the input, so something closer to HMAC would be hash(combine(hash("a", t), "a")). See http://en.wikipedia.org/wiki/Hash-based_messag

HMAC actually double-hashes the input, so something closer to HMAC would be hash(combine(hash("a", t), "a")). See http://en.wikipedia.org/wiki/Hash-based_message_authentication_code http://en.wikipedia.org/wiki/Hash-based_message_authenticati...