An Analytical Study Of Hybrid Cryptography And Implementation Of RSA With Hash Functions

Abstract

A key is a crucial factor in any cryptographic system. Devoid of a key, the algorithm would not produce any fruitful result. Key is being used in encryption, decryption and other cryptographic algorithms such as digital signature schemes and MAC. The only thing that should be kept secret in a sound cryptosystem is the key so the key generation is important in implementation of cryptographic algorithms. In this research work the key generation module of the developed application package RSAAPP has been discussed which generates private and public keys in pairs using RSA and the corresponding private keys generated are encrypted using DES algorithm hence RSAAPP is a hybrid cryptosystem as it uses the power of both public and private cryptosystems. Digital Signature technique is widely being used to detect unauthorized modification to data and to authenticate the identity of the signatory. It is essential for secure transaction over unsecure/ open networks. The PKI (Public Key Infrastructure) based digital signature architecture is related with RSA algorithm and secure Hash functions (MD5 and, SHA variants). RSA algorithm is an asymmetric cryptographic method whose security is associated with difficulty of factorization and hash function is applied to the message to yields a fixed-size message digest. This research work explores the PKI architecture based digital signature and presents an efficient way of its implementation and discusses various issues associated with signature schemes based upon RSA and hash functions. The experimental result shows that the RSA key generation, signature generation and signature verification with different hash functions - MD5, SHA1 and SHA2 are quite fast in RSAAPP. SHA2 is much more secure then SHA1 and MD5. It provides excessive level of security for encryption and decryption in optimum processing time as compared to presently available applications and also achieves high security for digital signature in addition to decrease processing time and computational overheads.