SYNERGISTIC INTEGRATION OF CODE COMPRESSION AND ENCRYPTION IN EMBEDDED SYSTEMS By KARTIK SHRIVASTAVA A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE

of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science SYNERGISTIC INTEGRATION OF CODE COMPRESSION AND ENCRYPTION IN EMBEDDED SYSTEMS By Kartik Shrivastava August 2010 Chair: Prabhat Kumar Mishra Major: Computer Engineering Embedded systems are used in a wide variety of places today, from cell phones to automobiles. Architects aim to make embedded systems more powerful and space efficient as well as secure. Code compression techniques are promising for reducing the memory requirements, whereas existing encryption techniques are widely used for application security. Code compression is traditionally used to reduce the code size by compressing the instructions with higher static frequency. However, it may produce a decompression overhead. Performance aware compression strategies try to improve performance through reduction of cache misses by utilizing the dynamic instruction frequency, but it sacrifices code size. Code compression and encryption can be integrated to make embedded system efficient (in terms of area, power and performance) as well as secure. This thesis studies a promising direction of compression followed by encryption to reduce the decryption overhead while maintaining the individual advantages of both code compression and encryption. This thesis also proposes a dual compression scheme that aims to simultaneously optimize code size reduction and performance improvement. Experimental results show that dual compression can achieve both compression ratios of up to 60% and an average performance improvement of 50%. Moreover, compression followed by encryption reduces the execution time of the encrypted binary by 40% on an average.