Description: Block cipher is widely used for data encryption in many years. However, the security level of these existing block ciphers is believed to be not enough in the coming decade because of the computational enhancement. Therefore, researches on block ciphers are still a hot issue in cryptology. Different techniques such as chaotic system and neural network are applied for performing block enciphering cryptosystem. However, many problems existed such as low security level, slow encryption speed and unacceptable data expansion. In this book, those problems will be reviewed and a new general model for the design of block-encipher cryptosystem using different nonlinear system such as neural network and chaotic system is introduced. The model mainly solves the problem of data expansion found in most cryptosystems based on nonlinear mapping. Two cryptosystems designed using the new model will be shown.
