1 Introduction
Cryptography is the art or science of keeping messages secret. People mean different things when they talk about cryptography. Children play with toy ciphers and secret languages. However, these have little to do with real security and strong encryption. Strong encryption is the kind of encryption that can be used to protect information of real value against organized criminals, multinational corporations, and major governments. Strong encryption used to be only in the military domain; however, in the information society it has become one of the central tools for maintaining privacy and confidentiality.