message-authentication-code

I know MAC is 4 first byte of last block encryption, and found this CMAC explanation here but it's kinda hard to understand. And maybe there are already some CMAC AES questions but I'm sorry I can't understand it well. Anyone can explain how to calculate CMAC? and if necessary with some example code in C#. Thanks First you need to derive two subkeys from your AES key. The algorithm is described well in RFC4493 , but I will include some code samples here for reference. For this, you will need the AESEncrypt function, which you can write using dotNet AesCryptoServiceProvider : byte[] AESEncrypt