A scalable trace and revoke scheme with security enhancements

Publishing digital content covered by intellectual property or copyright is faced by the challenge of countering illegal access to the digital good, while still enabling consumers to exercise their usage rights on purchased contents. Digital rights management (DRM) systems consist of architectures, protocols and technologies aimed at providing satisfactory solutions to the above problem. Trace and revoke schemes present one attractive cryptographic solution. This paper presents a scalable trace and revoke scheme that enables users verify their secret keys and thus protects them against corrupt ones due to malicious distributors or errors in communications. Moreover, the scheme is scalable supporting an unlimited number of revocations. Furthermore, the users secret keys are renewed which makes the task of external adversaries and traitors more difficult. In addition, broadcast messages are secure against chosen ciphertext attacks.