Symmetric encryption message authentication - arealive/Viper GitHub Wiki
Symmetric ciphers are commonly used to achieve other cryptographic primitives than just encryption.[citation needed]
Encrypting a message does not guarantee that this message is not changed while encrypted. Hence often a message authentication code is added to a ciphertext to ensure that changes to the ciphertext will be noted by the receiver. Message authentication codes can be constructed from symmetric ciphers (e.g. CBC-MAC).[citation needed]
However, symmetric ciphers cannot be used for non-repudiation purposes except by involving additional parties.1