When I decided that I wanted to learn Crypto, I found out that the Probability and Stats classes I took *AHEM* years ago were actually pertinent...and also pretty much forgotten. So I went searching on the web. I needed to brush up my calculus and shake the dust out of the Stats portion of my brain.
During my quest, I found a number of texts that were immensely useful, but I also found some resources on the web that I put directly to use.
These include:
I hope this helps. Good Luck.
C-.