Date Added: Mar 2011
In this paper, a pair of symmetric block ciphers has been developed for encryption and decryption of text file. The characters in the file are represented by the ASCII codes. A substitution table and a reverse substitution table are formed by using a key. The process of encryption and decryption is carried by using linear algebraic equations. However, the cryptanalysis has been discussed for establishing the strength of the algorithm. Result and analysis exhibits that the current algorithm works well and more secured to break the cipher.