In cryptography, CMAC is a block cipher-based message authentication code algorithm. It may be used to provide assurance of the authenticity and, hence, the integrity of data. This mode of operation fixes security deficiencies of CBC-MAC (CBC-MAC is secure only for fixed-length messages).

What is CMAC used for?

In cryptography, CMAC is a block cipher-based message authentication code algorithm. It may be used to provide assurance of the authenticity and, hence, the integrity of data. This mode of operation fixes security deficiencies of CBC-MAC (CBC-MAC is secure only for fixed-length messages).

What is HMAC and CMAC?

Generally CMAC will be slower than HMAC, as hashing methods are generally faster than block cipher methods. In most cases HMAC will work best, but CMAC may work better where there is embedded hardware which has hardware accelleration for block ciphers. For this, CMAC would likely run faster than HMAC.