In the past few years elliptic curve cryptography has moved from a fringe activity to a major system in the commercial world. This timely work summarizes knowledge gathered at Hewlett-Packard over a number of years and explains the mathematics behind practical implementations of elliptic curve systems. Since the mathematics is advanced, a high barrier to entry exists for individuals and companies new to this technology. Hence, this book will be invaluable not only to mathematicians but also to engineers and computer scientists who want to actually implement such systems.