Date Added: Sep 2012
Security of data in army stations is an important issue. In early systems, at the time of information transmission between two army stations, it can be hacked by terrorists, spies and enemies. Cryptography is a very important system employed for this purpose. There are various types of algorithms available for encryption and decryption of data and new algorithms are evolving. Polyalphabetic substitution cipher is a strong algorithm used for security of data in army stations. In this paper, various techniques of security of data and one the algorithm using polyalphabetic substitution cipher are discussed.