whenever security in communication is discussed, three things that come to mind is authentication,integrity, and data encryption. Although encryption and authentication are the major topics that needs to be taken care of, integrity of the data transferred also needs a major attention.
What problems are addressed with the help of integrity check?. Imagine that you are communicating with your friend through a chat client. How will your friend's machine know that the message he received is exactly the same message that you send?. And how will he verify that the message was not altered in the middle.
