Thought id share this as I have just started the cryptography course and I must say it is excellent. Highly recommended.
The computer security looks good too. I must warn its not for the faint hearted he does pack a *lot* of information in in a short time frame.
Coursera is committed to making the best education in the world freely available to any person who seeks it. We envision people throughout the world, in both developed and developing countries, using our platform to get access to world-leading education that has so far been available only to a tiny few. We see them using this education to improve their lives, the lives of their families, and the communities they live in.
https://www.coursera.org/