Internet is the prime vehicle to disseminate information from one place to another. Providing security to data is a major issue in transmitting data. One way of providing security to the data is encryption and decryption. Normal encryption is the way of changing the plaintext into cipher text using encryption and decryption algorithm and key. Literature reported different methods for encryption. An attempt is made in this paper to propose a modified encryption and decryption process performed with modified cellular automata rules. Cellular automata is idealized parallel processing machine which depends upon the cell value which is updated based on updating rule, which involves the cell and other cell values in a particular neighbourhood .Discrete references were made in the literature on the application of cellular automata rules. However lot more work remains to be done in this area. An attempt is made in this paper to provide encryption and decryption with cellular automata rules, using Data Encryption Standard (DES) and Advance Encryption Standard (AES) algorithms. They are operated at various stages, with the number of stages involved in sequential and cellular automata operating parallel. The major contribution of present work is, to develop methodology for identifying and application of 1D and 2D cellular automata rules and to fix the issues and challenges there in. A modified cellular automata set of rules are considered to develop 3D cellular automata rules for improved safety. Further a comparison is provided between existing 1, 2D automata rules versus the modified 3D cellular automata rules with respect to certain parameters. Keywords : Internet, Security, Cipher text, Plaintext, Cell value.

With the exponential growth of information being transmitted as a result of various networks, the issues related to providing security to transmit information have considerably increased. Mathematical models were proposed to consolidate the data being transmitted and to protect the same from being tampered with. Work was carried out on the application of 1D and 2D cellular automata (CA) rules for data encryption and decryption in cryptography. A lot more work needs to be done to develop suitable algorithms and 3D CA rules for encryption and description of 3D chaotic information systems. Suitable coding for the algorithms are developed and the results are evaluated for the performance of the algorithms. Here 3D cellular automata encryption and decryption algorithms are used to provide security of data by arranging plain texts and images into layers of cellular automata by using the cellular automata neighbourhood system. This has resulted in highest order of security for transmitted data.