An Involution Function-Based Symmetric Stream Cipher

The use of cryptography meaning the art of secret writing for securing information shared over an open medium is an old methodology but its importance in the present scenario has increased tremendously. With the increase in the computing power of an eavesdropper, it has become unavoidable to look for a better and better cryptographic primitive that provides a level of security while keeping a check upon the time consumed to encrypt and decrypt the data. We have used an involution function to produce a symmetric stream cipher. Involution functions have the property that when functioned again they outputs the original variable. We have analyzed our work with respect to the execution time and compared it with the standard AES-128 algorithm. The result shows a much lesser time is required to encrypt data of same size with the proposed approach as compared to AES-128 and other block ciphers.