[Vegenoid]

I wanted to have a better understanding of crypto, simply to feel more confident in writing programs that use existing protocols, and started 'Real-World Cryptography' by David Wong. I'm about 3/4 through, and I've been happy with it. It is light on math, but does go into it a little bit - it seems designed for the kind of person who isn't comfortable using something until they understand how it works under-the-hood, but doesn't actually need to do any under-the-hood work.

It has taught me enough that I think I could compose a protocol out of primitives that on the surface appears to do what I've intended it to do. It has also taught me that there are many subtleties that can completely break a protocol, combining primitives can lead to unexpected weaknesses, and many people who understand crypto far better than I ever will have created broken protocols out of secure primitives.

I'm not sure it's the book you're looking for, but I think it's a good book if you want to understand crypto, but not design your own.