Cryptography is just one piece of the security puzzle, along with SSL/TLS, certificates, digital signatures, and so on. This article explains how to use PHP to implement the most common cryptographic algorithms. In addition to describing PHP's default encryption functions, you'll see how to use a wide variety of cryptographic libraries and packages.

They start with a look at some of the built-in functions like md5, sh1 and crypt as well as a table detailing the different encryption methods (like mcrypt, mhash or crypt_blowfish). They follow this up with examples of some of them including a method for making secret keys with the Crypt_DiffieHellman PEAR Package.

Yes, my OpenID 2.0 PHP5 Consumer has finally been proposed to PEAR. This brings the OpenID fanaticism on PEAR to four packages: OpenID_Consumer, Services_Yadis, Crypt_HMAC2, Crypt_DiffieHellman.

He'll be working to get the code "further up to par" including Nonce validation, more consistent error reporting and other operation modes (like check_immediate). He's also included a screencast in the post for those not familiar with OpenID to get their first dose.