This page contains various web pages that were useful to me in my cryptology studies. No guarantee that they'll interest you! :)
I did some research on MD5, and wrote a C++ port of it. Go see the above link for more information. Hey, and Ron Rivest even referenced it on his crypto page!
SSL is the Secure Socket Layer standard, currently up to V3.0. Netscape put it forward; it is in very common use for secure web transactions.