Crypto 101 is an introductory course on cryptography, freely available for programmers of all ages and skill levels.
download their PDF: download now!
Start to finish.
Comes with everything you need to understand complete systems such as SSL/TLS: block ciphers, stream ciphers, hash functions, message authentication codes, public key encryption, key agreement protocols, and signature algorithms.
Learn by doing.
Learn how to exploit common cryptographic flaws, armed with nothing but a little time and your favorite programming language.
Forge administrator cookies, recover passwords, and even backdoor your own random number generator.