They do not. I am self taught in crypto (not an expert or even adept, but it's an interesting hobby) the texts always seem to cover basic number theory.
Edit: this is the book I used http://www.amazon.com/Introduction-Mathematical-Cryptography-Undergraduate-Mathematics/dp/1441926747
Most public-key cryptosystems these days are based on elliptic-curve arithmetic.
I would start with this book.
An Introduction to Mathematical Cryptography is a nice one for the math inclined students.
Note that in the first half of the book I used http://www.amazon.com/Introduction-Mathematical-Cryptography-Undergraduate-Mathematics/dp/1441926747. I swear professors who writes those kinds of coordinate changes, so there's your Lie group!