Abstract
This paper reports a cryptosystem designed for security of embedded systems. It is based on the theory of Cellular Automata(CA). The Cellular Automata based Cryptosystem(CAC) employs a series of transforms - simple, moderatel complex, complex - all generated with different classes of CA. The code size of CAC can be found to be lesser than that of an other scheme published in the literature. Cryptanalysis of the proposed scheme is reported along with similar analysis for two popular systems - DES and AES. Experimental results confirm that the security of the system is significantly better than DES and comparable to that of AES. Hardware-Soft are co-design of CAC with a simple CA hardware is also reported to establish the efficiency in terms of small code size and high speed of execution.