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.
In @cite_15 , propose a scenario where a content owner provides its (encrypted) content to users via a number of different (local) content distributors---which is similar to our scenario. Employing this scheme, users can buy licenses for content from a license server, acting as trusted third party. Once a license is bought, the user gets in possession of the decryption key which allows him her to access the content as often as desired. Differentiated license models are not intended in their approach---however, if license enforcement additionally took place on the client-side, differentiated license models could be implemented. As content download and license buying are done anonymously, none of the parties can build profiles of users' interest in content.
@cite_15
2039877753 2034884491 2166076876 2766544523
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. 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. The single-writer multi-reader searchable encryption (SMSE) allows an arbitrary authorized user to submit a valid search token and get the corresponding encrypted identifiers. In order to achieve fine-grained access control, the identifiers are encrypted by the attribute-based encryption. In this case, the user can decrypt a ciphertext only when the access policy in it matches the user’s attribute set. However, the server unable to determine whether the user can decrypt a certain ciphertext without the knowledge of the user’s attribute set. As a result, all the ciphertexts based on a search token have to be returned to the user, which causes unnecessary communication and decryption costs. In this paper, we propose a new SMSE scheme, in which the server just needs to return the ones which can be decrypted by the user rather than the whole search results. In order to achieve this goal, we present a server-side match technique with which the server can test whether the user can decrypt a ciphertext without knowing the user’s attribute set. Furthermore, the decryption computation is very efficient, irrespective of the structure of access policy. Therefore, both the communication and decryption overheads are dramatically reduced in our scheme.