VLSI implementation of a chaotic encryption algorithm with applications to secure communications

Abstract

Chaos has been emerging as a phenomenon that Micrographics. researchers claim can be applied in the communications area for security purposes. Several implementations of chaos schemes ranging from simple masking of an information signal with chaos to coding using the noise-like characteristics of chaos have been presented in the literature. Up to date, most of the experimental secure communications schemes employing chaos have been implemented with discrete components. While some VLSI implementations have been presented in the literature, most of them have been for the case of chaotic information masking. Several drawbacks for this simple masking case make this approach unfeasible for real communication purposes. A new approach for encrypting an information signal using a chaotic synchronous system and an innovative non-linear filter was proposed and experimentally verified with discrete components by Con-on and Hahs. In this thesis, the VLSI implementation of a similar secure communication system is presented. The mathematics behind the generalized Lorenz chaotic system and the Corrori and Hahs approach are developed and presented. One of the major contributions of this work is the VLSI implementation of a fully-differential Lorenz chaotic system which is the first of its kind. The oscillating frequency of this chaos system is externally programmable by varying the capacitor values of the system integrities. A fully-differential cyptosystem is designed and fabricated using the [], technology available through the MOSIS foundry. The baseband cryptosystem has a signal dynamic range of []1.5V using []3V power supplies and is capable of sustaining digital information rates of up to 100Kb/s.