Handbook of Applied Cryptography
cconnell writes "The Handbook of Applied Cryptography is now available free (for personal use) on the Internet. This is a $100 book. Note also the companion C source code for most of the crypto algorithms, written by James Pate Williams. There is some very cool code here!"
Did you download it? Didn't think so, troll. It's perfectly open and editable with no protections whatsoever.