We present a solution to the problem of privacy invasion in a multiparty digital rights management scheme. (Roaming) users buy content licenses from a content provider and execute it at any nearby content distributor. Our approach, which does not need any trusted third party--in contrast to most related work on privacy-preserving DRM--is based on a re-encryption scheme that runs on any mobile Android device. Only a minor security-critical part needs to be performed on the device's smartcard which could, for instance, be a SIM card.
@cite_4 present a privacy-preserving DRM scheme for two- and multiparty scenarios without needing a TTP. A user anonymously requests a token set from the content owner that allows anonymous purchase of content licenses from content providers. A drawback is that content providers are able to build usage profiles of content executions under a pseudonym. @cite_5 present a DRM scenario that allows users to anonymously buy software from any software provider and execute it at any computing center within the cloud. The users' permission to execute the software is checked before every single execution. Their solution is resistant against profile building. The authors suggest employing a software re-encryption scheme that is based on secret sharing and homomorphic encryption to achieve unlinkability of software executions towards the computing center. Their software re-encryption scheme is rather complex and implies a huge communication overhead. The approach is extended in @cite_18 by employing an adapted version of proxy re-encryption @cite_14 . The scheme makes explicit use of a service provider as a TTP.
@cite_5 @cite_18 @cite_14 @cite_4
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We propose a privacy-preserving digital rights management scheme for (future) cloud computing. Users buy software from software providers and execute it at computing centers. Our solution allows software providers to provide different license models, like execute at most n-times models. Users' anonymity and unlinkability of actions are preserved and thus, profile building is not even possible under (a) pseudonym. Privacy protection in the honest-but-curious model is achieved by combining ring signatures with an anonymous recipient scheme. We employ secret sharing in a unique manner that allows the software provider to expose the user's identity if the user commits fraud, e.g. by exceeding the execution limit n. We come up with a digital rights management (DRM) concept for cloud computing and show how license management for software within the cloud can be achieved in a privacy-friendly manner. In our scenario, users who buy software from software providers stay anonymous. At the same time, our approach guarantees that software licenses are bound to users and their validity is checked before execution. We employ a software re-encryption scheme so that computing centers which execute users' software are not able to build user profiles -- not even under pseudonym -- of their users. We combine secret sharing and homomorphic encryption. We make sure that malicious users are unable to relay software to others. DRM constitutes an incentive for software providers to take partin a future cloud computing scenario. We make this scenario more attractive for users by preserving their privacy. We present a privacy-friendly architecture for a future cloud computing scenario where software licensing and software payment plays a major role. We show how digital rights management as a technical solution for software licensing can be achieved in a privacy-friendly manner. In our scenario, users who buy software from software providers and execute it at computing centres stay anonymous. At the same time, our approach guarantees that software licences are bound to users and that their validity is checked before execution. Thus, digital rights management constitutes an incentive for software providers to take part in such a future cloud computing scenario. We employ a software re-encryption scheme so that computing centres are not able to build profiles of their users - not even under a pseudonym. We make sure that malicious users are unable to relay software to others. Due to rapid advances in the network communications field in recent years, the distribution of large-scale music contents has become easier and more efficient than ever before. However, the unauthorized distribution of copyright-protected content has emerged as a major concern. Accordingly, this paper presents a content distribution framework with a DRM capability for P2P networks. The robustness of the content distribution is ensured by using a network coding approach based on the Lagrange polynomial interpolation method. When the downloading peer within the network receives sufficient coded pieces, it not only reconstructs the associated blocks using a finite field Gaussian elimination method, but also creates its own copies of the coded pieces within these blocks and shares these copies amongst the other peers in the network. As a result, the distribution overhead imposed on the music provider is substantially reduced and the number of coded pieces within the network is significantly increased, thereby overcoming the ''last piece problem'' inherent in existing P2P schemes. In the DRM module of the framework, the RSA public-key cryptosystem is used to generate a unique digital fingerprint for every user within the network. The fingerprint is embedded within the music file in a protected form such that the music provider can establish the identification of any user performing an unauthorized distribution of the file. The experimental results confirm that the proposed framework provides an efficient and secure means of distributing large-scale copyright-protected music contents with no discernible degradation in the audio quality.