Khan Academy
What cryptographic hash functions are and what properties are desired of them. More free lessons at: http://www.khanacademy.org/video?v=0WiTaBI82Mc...
Khan Academy
Brit explains the Caesar cipher, the first popular substitution cipher, and shows how it was broken with...
What is Cryptography? A story which takes us from Caesar to Claude Shannon. Watch the next lesson:...
