Some cryptographic algorithms

Abstract

Cryptography is the practice and study of techniques for secure communication in the presence of third parties, called adversaries. Modern cryptography is heavily based on mathematical theory and computer science practice. Cryptographic algorithms are designed so that in practice they are hard to break by any adversary. In the present thesis consisting of two chapters first we have given a brief review of some important number theoretic concepts and results. Then we have discussed S-DES and DES algorithms for Secret key cryptography, RSA and DSA algorithms for Public key cryptography and at last a brief introduction of elliptic curves and their use in Cryptography is given.