Optical discs are the preferred media for storing and distributing digital information, especially software. The pervasive use of these discs in motivated by their low cost coupled with their versatility and durability. But advances in circuit technology have also boosted software piracy by making it easy to create high-fidelity copies of optical discs. Thor is a security scheme that aims to prevent unauthorized disc duplication and any illegal use of the data. Thor relies on a combination of software and hardware strategies using time-tested cryptographic algorithms to provide resistance to tampering and malicious operations. Currently, Thor exists only as a research proposal, not as a working prototype of a security mechanism. But a survey of available technologies suggests that implementing Thor is feasible.Thor presents a possible a new direction in the battle against piracy. Its acceptability, and the consequent realization of this concept, depends on how determined manufacturers are to defeat digital theft. A determined pirate can break most security mechanisms. But this proposal aims to discourage piracy by offering an innovative security technique.