We formally specify the recent DRM scheme of Nair et al. in the μ crl process algebraic language. The security requirements of the scheme are formalized and using them as the basis, the scheme is verified. The verification shows the presence of security weaknesses in the original protocols, which are then addressed in our proposed extension to the scheme. A finite model of the extended scheme is subsequently model checked and shown to satisfy its design requirements, including secrecy, fairness and resisting content masquerading. Our analysis was distributed over a cluster of machines, allowing us to check the whole extended scheme despite its complexity and high non-determinacy.