Final answer:
The inputs to a MAC function are a message and a secret key, while the output is a fixed-length code called the MAC tag or digest.
Step-by-step explanation:
The inputs to a MAC function are a message and a secret key. The message is the data that needs to be authenticated, while the secret key is a shared secret between the sender and the recipient.
The output of a MAC function is a fixed-length code called the MAC tag or digest. This tag is appended to the message and sent along with it. The recipient can then verify the integrity and authenticity of the message using the MAC tag and the shared secret key.
For example, in the HMAC (Hash-based Message Authentication Code) algorithm, the inputs are the message and the secret key, and the output is a fixed-length hash value.