International terrorism is not a new phenomenon, and it is a topic that has been subjected to substantial scholarly analysis. The prospect of computer network attacks by terrorists, however, poses new challenges to the law and legal institutions applicable to the efforts of law enforcement officials and others to prevent and punish acts of international terrorism. In this article Professor Murphy explores the nature of these challenges, as well as steps that have been taken to meet them, and sets forth some concluding observations as to possible future developments.