1. What do you mean by message authentication?
Ans.: Message authentication refers to the mechanism used to ensure that the integrity of the received message has been preserved - that the message has not been altered during transmission. It also assures the receiver that the message has originated from the intended sender and not from any intruder. Thus, a message is said to be authentic if the message has not been altered and has come from the actual sender.
2. What types of attacks are addressed by message authentication?
Ans.: The messages transmitted across a network are subject to various attacks. The types of attacks that are addressed by message authentication are as follows: