A Message Authentication Code (MAC) is a short piece of information used to confirm the integrity and authenticity of a message. It ensures that the data has not been altered and verifies that it comes from a specific sender.In practice, a MAC is generated by taking the original message and a secret key, then processing them through a cryptographic algorithm. This produces a unique code that is appended to the message. When the recipient receives both the message and the MAC, they can use the same key to compute their own MAC from the message. If their MAC matches the one that was sent, the message is deemed authentic and unaltered.MACs are important for preventing unauthorized changes to transactions and ensuring that sensitive information remains secure. They play a key role in maintaining trust among parties involved in financial operations. By using MACs, users can confidently verify that the data they receive is genuine and that it hasn’t been tampered with during transmission.