Yashar Salami - Department of Computer Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran
Ali Asghar Pourhaji Kazem - Department of Computer Engineering, Tabriz Branch,Islamic Azad University, Tabriz, Iran

Cryptography is the science that investigates and studies the principles and methods of transmitting, as well as storing information in a safely manner. By the advances in science and technology and getting access to advanced information facilities, the use of different levels of information security becomes more and more necessary. Due to the increasing growth of computer networks and employing of different techniques to confidential information, understanding the state of art information security procedures is vital and very important. It can be said that encryption algorithms are the infrastructure for all network security protocols. Encryption algorithms are divided into symmetric and asymmetric categories, based on the type of encryption. The symmetric algorithms mostly employ the structure of Feistel Network; on the other hand, the asymmetric algorithms conform to the mathematical structures. On that basis, different encryption methods have been discussed and their functions would be introduced and then, every algorithm would be compared.

Cryptography, Encryption, Decryption, Security