5.6 Summary

In this chapter, we covered entity authentication, a cornerstone of secure communication. We discussed what identity is and how identification protocols fundamentally work. We also covered basic factors for identification and discussed the connection between authorization and authenticated key exchange. We also worked out the differences between message authentication and entity authentication.

We covered password-based authentication, including challenges related to storing passwords as well as the fundamental shortcomings of password-based authentication. We then discussed how cryptographically secure challenge-response protocols avoid these drawbacks and introduced challenge-response protocols based on symmetric keys, hash functions and their key-dependent counterparts (also known as message authentication codes (MACs)), and public-key encryption.

In the next chapter, we will take a first glance at Transport Layer Security, the means to provide secure communication over...