Block Cipher Encryption based on Random Substitution

Securing data is essential, whether it is in commercial or armature environment. Exchanging data over the network is risky due to illegitimate access and possible modification during communication. Certain attacks on data/message may take place. To minimize these problems, there are several techniques has been invented.

To secure data, primarily some cryptic techniques are used. In ancient times different types of substitution techniques were used, later on some mathematical models [2] [6] were devised to encrypt and decrypt the data. In present days both of those techniques are combined to achieve solutions associated with those problems. In our work we have used the combined technique. We have used substitutions to make the data random, to enable this task we have used the values comprises the keys then performed XOR operations using modified data (after substitution) and keys. The whole process is capable to encrypt and decrypt a file.