Which process is used to verify the integrity of a message?

• A. Message compression
• B. Message encryption
• C. Message authentication
• D. Message encoding

Answer: (C)

The process used to verify the integrity of a message is message authentication. Message authentication ensures that the message received is the same as the message that was originally sent, confirming that it has not been altered during transmission. This is accomplished through various mechanisms such as digital signatures or hash functions, which create a unique hash for the original message. When the receiver gets the message, they can generate a hash of the received message and compare it to the hash sent along with the message. If the hashes match, it indicates that the message has not been tampered with, thus verifying its integrity.

Message compression, on the other hand, reduces the size of the data for efficiency but does not provide any assurances regarding integrity. Message encryption focuses on keeping the message confidential and secure from unauthorized access, rather than ensuring its integrity. Message encoding is about transforming data into a different format, which does not necessarily relate to verifying whether the message remains unchanged. Therefore, message authentication is the correct process for verifying message integrity.