Information Theory, Coding and Cryptography

Chapter 9

Cryptography

9.1  INTRODUCTION

Cryptography is the study of mathematical techniques related to aspects of information security such as confidentiality, data integrity, entity authentication, and data origin authentication. It is derived from the two Greek words kryptos’, which means ‘secret’, and ‘graph’, which means ‘writing’. Cryptography is not the only means of providing information security, but rather one set of techniques. Cryptography helps to store sensitive information or transmit it across insecure networks (like the Internet) so that it cannot be read by anyone except the intended recipient.

While cryptography is the science of securing data, cryptanalysis is the science of analyzing and breaking secure communication. Classical ...