Humanizing the Security of Rail Fence Cipher Using Double Transposition and Substitution Techniques

Cryptography is a science that applies complex mathematics and logic to design strong encryption methods. Achieving strong encryption, the hiding of datas meaning, also requires perceptive leaps that allow creative application of known or new methods. So cryptography is also an art. We can say now that Cryptography is the art of achieving security by encoding messages to make them non-readable. Cryptography, as the most important aspect in the never ending evolving information technology era, is being criticized in its aspect. Information outbreaks make users doubtful on relying on their own information in current cryptosystems. Cryptography is used to maintain the secrecy and integrity of information, Whenever it is exposed to potential attacks. Cryptography comes from the Greek words for secret writing. The plain text is encrypted into the corresponding cipher text, using an algorithm and a key. Substitution and Transposition are two Techniques used for converting data into non-readable form. Rail Fence Cipher is an example of Transposition technique. In this paper we have proposed a cipher that uses basic encryption techniques of substitution and transposition. A double columnar transposition followed by a double substitution is applied on a Rail Fence cipher in order to make it a stronger and a more secure cipher