Читать книгу Security Engineering - Ross Anderson - Страница 181

The commonly used building blocks in asymmetric cryptography, public-key encryption and digital signature are based on number theory. I'll give a brief overview here, and look in more detail at some of the mechanisms in Part 2 when I discuss applications.

The basic idea is to make the security of the cipher depend on the difficulty of solving a mathematical problem that's known to be hard, in the sense that a lot of people have tried to solve it and failed. The two problems used in almost all real systems are factorization and discrete logarithm.