Summary

In this chapter, we examined various modes of cryptography available within PHP, including shared secret and public key methods. We introduced ourselves to two of PHP's bundled extensions: mcrypt and openssl, and identified some of PHP's core functions useful in building simple encryption algorithms of our own.

Using the concepts covered in this chapter, you should be able to safeguard your own private data, as well as the private data of your customers. You will also be able to trade information securely across the Internet and establish reliable identification of the parties you communicate with.