Message Integrity Controls is a special value that is calculated based on the message contents and added to the message to be sent;
To protect against an intentional integrity attack, we need to use one of the three bottom choices:
- Digital Signatures
We can generate a hash of a message that has been concatenated with a secret key, which is an example of HMAC. The HMAC uses a standard hash function (MD5 or SHA-1) and hashes the message with a secret key, but without a secret key algorithm such as DES.