Date of Award

1-1-1997

Degree Type

Thesis

Degree Name

Master of Science

School

School of Mathematics, Information Technology and Engineering

Faculty

Faculty of Science, Technology and Engineering

First Advisor

Dr T. J. O'Neill

Second Advisor

Professor A. C. Watson

Abstract

Contact-based smart-cards, which comply to the International Standard IS0-7816, communicate with their associated read/write machines via a single bi-directional serial link. This link is easy to monitor with inexpensive equipment and resources, enabling captured data to be removed for later examination. In many contact-based smart-cards the logical abilities are provided by eight-bit microcontroller units (MCU) which are slow at performing effective cryptographic functions. Consequently, for expediency, much data may be transferred in plain-text across the vulnerable communications link, further easing an eavesdropper's task. Practitioners in military communications protect transmitted information by varying a link's carrier frequency in an apparently random sequence that is shared secretly between the sender and the authorised receiver. These multiplexing techniques, known as frequency or channel-hopping, serve to increase the task complexity for and/or confuse potential eavesdroppers. The study seeks to ascertain the applicability and value of protection provided by channel-hopping techniques, when realised with minimal additional overhead of microcontroller resources to the contact-based smart-card communications link. The apparent randomised shuffling of data transferred by these techniques has the potential benefit of deterring those observers who may lack the equipment and expertise to capture and decode the communicated message.

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