Message authentication

While Symmetric Cryptography ensures the confidentiality of data, it does not ensure the authenticity and integrity of the sender.

Introducing authentication protects against active attacks to a system, by verifying if the received message came from the expected source, and that it has not been tampered with (integrity). Conventional cryptographic algorithms can be made to ensure authenticity by including some authentication tag in the message, but typically it is provided through some other means.