I have written this book partly to correct a mistake. It's just not true. Cryptography can't do any of that.
Cryptography is a branch of mathematics.
And like all mathematics, it involves numbers, equations, and logic. The error of Applied Cryptography is that I didn't talk at all about the context. I talked about cryptography as if it were The Answer TM . The result wasn't pretty. Readers believed that cryptography was a kind of magic security dust that they could sprinkle over their software and make it secure.