For the latter, Applied Cryptography, by Bruce Schneier is the standard response, and surprisingly readable. I’ve read other books in the field, but nothing I can think of that’s quite as much a “textbook”, so this recommendation may or may not officially count.
And of course, a caveat applies to any book on cryptography: don’t read it and start coding your own algorithms—anyone can invent a cryptosystem he can’t break himself. If you’re planning on doing development, the only safe way to handle this stuff is to use well reviewed, well maintained libraries. A textbook will give you a sense of what’s available and how things might fit together.
The math, or application thereof?
For the latter, Applied Cryptography, by Bruce Schneier is the standard response, and surprisingly readable. I’ve read other books in the field, but nothing I can think of that’s quite as much a “textbook”, so this recommendation may or may not officially count.
And of course, a caveat applies to any book on cryptography: don’t read it and start coding your own algorithms—anyone can invent a cryptosystem he can’t break himself. If you’re planning on doing development, the only safe way to handle this stuff is to use well reviewed, well maintained libraries. A textbook will give you a sense of what’s available and how things might fit together.