Related Work

Much of the work on encryption concentrate only on the design and security issues of the algorithm concerned. But in real systems performance and implementation costs are as important as the security. This is further amplified in a personal environment where some devices like Palm Pilot, for example, are inherently limited with respect to their processing ability, battery life etc., which in turn could severely affect the the very feasibility of performing encryption.

The work that comes closest to ours is a study by Bruce Schneier [Schneier99] which gives the relative performance of 15 different proposed submissions for AES (Advanced encryption standard) on 8-bit 32-bit and 64-bit machines. It also gives memory requirements of the algorithms on 8-bit smart cards. But this study leaves out the power requirements which are very important considering the portable devices in a personal environment. Another study by J. Goodman and A. Chandrakasan [Goodman] explores the low power encryption techniques for wireless networks. This work explores only the hardware encryption techniques and suggest how best encryption can be optimized in hardware for low power consumption. Other work study optimizations for various algorithms.

All of the above work focus on the performance and costs with respect to one or two factors at the best. They do not comprehensively analyze all the attendant costs which are prohibitive for portable devices. Our work will consolidate all earlier work and add to those, to answer the question of universal encryption in a personal environment. This will provide an application developer with an immediate reference to reason about the use of sophisticated knobs to specify security policies in his applications.