Protecting Cryptographic Keys: The Trace-and-Revoke Approach

D igital content is easy to generate, transfer, and reproduce. Although this makes the technology attractive and has brought about its proliferation, it has also become a major source of ownership-information violations with respect to either copyright or the privacy of individuals and businesses. With the increasing amount of readily available digital content and the resulting constant reduction in storage media prices, we can expect the phenomenon of ownership violation to increase steadily. Ownership protection presents a fundamental social issue: Society must define its usage rules and accompany those rules with appropriate means to enforce them via, for example, legislation. However, technological developments can certainly help shape the ground rules by raising technical and social barriers against the violators. What ownership protection can technology offer these days? The state-of-the-art methods that can help to limit copyright and intellectual-property ownership violations fall into three categories: