Let's assume there are two people who wants to exchange a message across a network, Bob and Alice. Bob wants to send Alice a file named Test.txt with its contents, ABCD. Bob wants to ensure Alice receives the message and that its contents remain unaltered.

A process, known as hashing, creates a unique string of alphanumeric characters, known as a hash. The hash represents the context of the message. In the scenario, Bob sends both the file, Test.txt, and its hash values to Alice. When Alice receives the file and the hashes from Bob, Alice also creates her hashes of the file. Alice would then compare her hash values with the ones received from Bob, if both values match, the file was not modified during transmission and the integrity was maintained: