Property-Based Broadcast Encryption for Multi-level Security Policies
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- Adelsbach A., Huber U., Sadeghi AR. (2006) Property-Based Broadcast Encryption for Multi-level Security Policies. In: Won D.H., Kim S. (eds) Information Security and Cryptology - ICISC 2005. ICISC 2005. Lecture Notes in Computer Science, vol 3935. Springer, Berlin, Heidelberg
Most current Digital Rights Management (DRM) systems rely on the doubtful assumption that all devices are equally trustworthy. This allows a pirate to obtain access if he undetectedly breaks just one arbitrary device. As there is a multitude of different devices, trust assumptions and policies should depend on the security level of each device type. For each content item to be distributed, the content providers should be able to base their access decision on various properties that the devices might have, such as the devices’ tamper resistance, geographical region, output interface or device model.
We propose a hierarchical property-based broadcast encryption scheme enabling a variety of new business models. It operates with an arbitrary number of properties, including one hierarchical property such as tamper resistance. The scheme is secure and more efficient than existing Broadcast Encryption (BE) schemes in the hierarchical setting. As the first building block, we formalize the notion of properties with respect to BE and show an approach for representing them in a binary tree structure. As the second building block, we use existing BE schemes to achieve short ciphertexts. Specifically, we enhance the Complete Subtree scheme with pseudo-random chains to embed the hierarchical property.
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