任何的mac算法都可以使用标准的hash功能，比如MD５或者sha－１，这种情况下，强度取决于hash功能，和最后的结果的比特串。密匙是关键。-HMAC is a message authentication code (MAC) and can be used to verify the integrity and authentication of a message. It involves hashing a message with a secret key. As with any MAC, it can be used with standard hash function, such as MD5 or SHA-1, which results in methods such as HMAC-MD5 or HMAC-SHA-1. As with any hashing function, the strength depends on the quality of the hashing function, and the resulting number of code bits. Along with this the number of bits in the secret key is a factor.