Parag A. Guruji, Walchand College of Engineering, India

Evolution in the communication systems has changed the paradigm of human life on this planet. The growing network facilities for the masses have converted this world to a village (or may be even smaller entity of human accommodation) in a sense that every part of the world is reachable for everyone in almost no time. But this fact is also not an exception for coins having two sides. With increasing use of communication networks the various threats to the privacy, integrity and confidentiality of the data sent over the network are also increasing, demanding the newer and newer security measures to be implied. The ancient techniques of coded messages are imitated in terms of new software environments under the domain of cryptography. The cryptosystems provide a means for the secured transmission of data over an unsecured channel by providing encoding and decoding functionalities. This paper proposes a new cryptosystem based on four levels of encryption. The system is suitable for communication within the trusted groups.

Matrix transformation, Fractionification, Re-integerization, Change of radix