| Cryptography and error detection/correction play essential roles in modern data communications. In most cases, they are studied and applied separately. In this project, a novel high-speed cellular automata based block cipher and a system design of fault tolerant cryptosystems are presented.; Firstly, a cellular automata (CA) based block cipher algorithm (CA256-2) is designed to provide the high-speed encryption/decryption. CA256-2 is a 128-bit block cipher with a 256-bit primary key. Compared to other CA encryption schemes, CA256-2 can automatically generate a valid rule from a random number, so it eliminates the large rule storage required by the other CA schemes. The novel “non-symmetric” approach proposed in the CA256-2 algorithm can provide the decryption much faster than the encryption, which is impossible in other block ciphers. CA256-2 provides a good tradeoff between security level and encryption/decryption performance. The key space for the primary key is 2256 while its software encryption rate and decryption rate are 250 Mbps and 465 Mbps respectively on a Pentium 111450 MHz PC.; Secondly, a novel systematic approach is proposed to integrate both the fault tolerance and data security. A two-dimensional (2-D) Hash function is thus defined to provide the digital signature and serve as “check-sums” for error detection and error correction. By sharing the same computation for both the digital signature and error detection/correction, the total computation overhead is significantly reduced. The proposed technique is able to authenticate the origin of the data, provide the data privacy, and detect and correct up to three errors.; The proposed fault tolerant cryptosystems are particularly ideal for transferring large amount of data that require data source authentication and data privacy. CA256-2 can also be used alone for many multimedia applications, such as video/audio on demand, wireless Internet, and video conferencing in which high-speed encryption/decryption is needed. |
