Prior to the general availability of high speed Internet, the spread of piratedsoftware required the transfer of a physical copy like a disk, which limited therate at which illegal software could be distributed. The low transfer raterestricted software piracy to levels which producers found acceptable becausethe associated losses could be absorbed. Large scale cases of piracy were rareand when they did occur the legal system provided suitable retribution. However,recent advances in computer technology have made the need for a physical copyobsolete. Piracy is now a widespread, decentralized problem in which millions ofindividuals take part. Without technical means of identifying pirated software,the protection afforded by the legal system is no longer easy to enforce or costeffective.The research in this dissertation addresses the threat of software piracythrough the exploration of two techniques: software watermarking and softwarebirthmarking. Neither of these techniques can be used to prevent software theftentirely. Instead, they are used to detect occurrences of theft after the fact.One of the limiting factors of the protection provided by the legal system isthat it cannot be used to identify an incidence of piracy. Softwarewatermarking and birthmarking fill this gap, thus providing complimentaryprotection to the established legal protection. In this research, we analyze thestate of the art in both software watermarking and birthmarking and we propose anovel scheme in each of the areas which make significant improvements overexisting techniques.

A modular reuse-based design methodology has been one of the most important factors in improving hardware design productivity. Traditionally, reuse involves manually searching through repositories for existing components. This search can be tedious and often unfruitful. In order to enhance design reuse, an automated discovery technique is proposed: a reference circuit is compared with an archive of existing designs such that similar circuits are suggested throughout the design phase. To achieve this goal, methods for assessing the similarity of two designs are necessary. Different techniques for comparing the similarity of circuits are explored utilizing concepts from different domains. A new similarity measure was developed using birthmarks that allows for fast and efficient comparison of large and complex designs. Applications where circuit similarity matching can be utilized are examined such as IP theft detection and reverse engineering. Productivity experiments show that automatically suggesting reusable designs to the user could potentially increase productivity by more than 34% on average. / Ph. D.