Fundamentals of symmetric cryptography

Abstract

It is widely recognized that data security will play a central role not only in the design of future IT systems, but also in all kind of systems in which electronic data are exchanged. Cryptology is the main tool to realize data security. Cryptographic primitives will not only secure the data communication, but will provide safety and reliability of the given system. The latter is sometimes far more important for certain applications which involve automated control based on the data communication between different devices. Cryptology provides two different kinds of algorithms, namely symmetric and asymmetric (public-key) algorithms. This chapter gives an introduction to symmetric key cryptography and its subgroups - block ciphers and stream ciphers. We also provide short descriptions of the most commonly used algorithms in industry: DES and AES. We will focus on their special properties from an implementation point of view. Major concentration will be on software and hardware implementations of DES, 3-DES, AES and different modes of operations of block ciphers so that they can be used also as stream ciphers. © 2006 Springer-Verlag Berlin Heidelberg.