What is message authentication

Question

Explain what is meant by the term message authentication? Describe the classes of message authentication function.

Answer 1

It is defines as a procedure which verifies if the received message comes from the assigned source has not been changed.

Classes of message authentication function are as considered as:

a) Message encryption : The whole cipher text could be used for the purpose of authentication.

b) Message Authentication Code : It is defined as a function of the message and secret key generate a fixed length value.

c) Hash function : This function maps the message of any length to the fixed length that serves as the authentication.