2.5 Authentication
Authentication is the ability to identify the source of the communication, both for the communicating parties and for the information itself. In other words, authentication refers to a cryptographic mechanism ensuring that the identity of communicating entities can be verified and that the source of a received message can be verified. Any two parties entering into a secure communication should authenticate each other and the data received with respect to their origin. This hints at the fact that there are actually two kinds of authentication: one to verify identities (entity authentication) and another to verify data origin (message authentication).
Authentication is one of the most important security goals in cryptography. After hash functions and digital signatures were discovered, authentication and confidentiality were classified as independent information security objectives [117]. Without authentication, however, there can be no genuine confidentiality because...