Date of Award

Spring 2008

Document Type



Mathematics, Engineering & Computer Science

First Advisor

Anthony Szpilka

Second Advisor

Philip Rose

Third Advisor

Mary Keefe


Modem cryptology has allowed business to expand at an incredible rate by allowing people to transact business securely online. A common encryption process for encoding and decoding information utilizes a linear feedback shift register (LFSR) to generate a quasi-random string ofbinary digits. This “key stream” is then combined with the digits of the original or “plain text” using the exclusive-or logical operation, to create the encrypted or “cipher text.” Using modem circuit components, a circuit to implement this type of encryption was constructed and evaluated. The circuit’s operation was then simulated by the specialized computer program Cryptographic Analysis Program (CAP). Using CAP allowed for multiple methods of generating quasi-random bit strings: both the LFSR and the method of cellular automata were examined here. After these two key stream generators were analyzed, some observations were made concerning the general security of each.