We used Christof Paar's book in my crypto class this past semester. The book was great (much better than my professor) and the explanations of how number theory

We used Christof Paar's book in my crypto class this past semester. The book was great (much better than my professor) and the explanations of how number theory makes up the majority of the math our modern encryption uses were great. I had never heard of a Galois field until that course, and his text book did a great job explaining what they are and why it makes AES possible. In general, encryption algorithms are so neat. We take some obscure (at least to me) math topics and we can use them in ways to create these incredible algorithms. Right now, the most exciting thing in the world of crypto for me is the NIST competition for a post-quantum crypto algorithm. I'm very excited to see what comes out on top.