In the past, Cryptography was used in keeping military information, diplomatic correspondence secure and in protection of national security. Nowadays, the range of cryptography applications have been expanded a lot in the modern area after the development of communication means; cryptography is essentially required to ensure that data are protected against penetrations. This is used to ensure that the contents of a message are confidentially transmitted and would not be altered. In this paper, we have implemented a cryptosystem (encrypting/decryption) for text data using both Data Encryption Standard (DES) and Rivest-Shamir-Adleman (RSA) cryptosystem. The asymmetric algorithm was used for the key encryption and decryption process because it provides a means to deliver keys on a secure channel, while the data to be sent will be encrypted and decrypted using the symmetric algorithm. This system was designed to accomplish a number of security features such as authentication, confidentiality, integrity, and non-repudiation. Also the combination of the speed and strength of the symmetric algorithm with the robustness and key management capability of the asymmetric algorithm, thereby producing an enhanced encryption algorithm and we employed text data as our experimental data.
Key words: Cryptography, encrypion, decryption, cryptosystem