Building Secure Software: How to Avoid Security Problems the Right Way

Appendix A. Cryptography Basics

“Seven years ago I wrote another book: Applied Cryptography. In it I described a mathematical utopia: algorithms that would keep your deepest secrets safe for millennia, protocols that could perform the most fantastical electronic interactions—unregulated gambling, undetectable authentication, anonymous cash—safely and securely. In my vision cryptography was the great technological equalizer; anyone with a cheap (and getting cheaper every year) computer could have the same security as the largest government. In the second edition of the same book, written two years later, I went so far as to write: ‘It is insufficient to protect ourselves with laws; we need to protect ourselves with mathematics.’ It’s just not ...