Asymmetric Key Encryption Algorithms

Abstract

Cryptography is one of the main constituents of computer security. Public cryptography is the art of protecting information by transforming it (encrypting it) into an unreadable format, called cipher text. Only those who possess a secret key can decrypt the message into plain text. This paper reviews five commonly used asymmetric key cryptography algorithms namely RSA, Diffie–Hellman, El Gamal, DSA and ECC and present their comparative study. 1. Introduction

Today security is the challenging aspect in internet and network application. Cryptography is the study of mathematical techniques related to various aspects of information security, such as confidentiality or privacy, data integrity and entity authentication. It is not the

There exist many symmetric key encryption algorithms. Several hundreds of these are proposed over the years and even though a lot were found not to be secure, there exist many cryptographically strong ones. The situation is quite different for asymmetric algorithms. There are only three major families of public key algorithms which are of practical relevance. They can be classified based on their underlying computational problem. Integer factorization schemes are based on the fact that it is difficult to factor large integers. The most prominent representative of this algorithms family is RSA. Discrete Logarithm Schemes are based on what is known as the discrete logarithm problem in finite fields. The most prominent examples include the Diffie Hellman key exchange, El Gamal encryption or the digital signature algorithm. (DSA). A generalization of the discrete logarithms algorithms are elliptic curve (EC) public-key schemes. The most popular examples include Elliptical Curve Diffie Hellman key exchange (ECDH) and Elliptical Curve Digital Signature Algorithm (ECDSA). There are no known attacks against any of the schemes if the parameters, especially the operand and key lengths are 17 chosen carefully. It is important to note that each of the three families can be used to provide the main public key mechanisms of key

Diffie–Hellman key exchange is a specific method of exchanging cryptographic keys. This method allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure communications channel. This key can then be used to encrypt subsequent communications using a symmetric key cipher. The algorithm is itself limited to the exchange of keys. The Diffie–Hellman key exchange algorithm depends for its effectiveness on the difficulty of computing discrete logarithms