IACR News item: 12 January 2015
Yannis Rouselakis, Brent Waters
ePrint ReportOur construction achieves maximum versatility by allowing multiple authorities to control the key distribution for an exponential number of attributes. In addition, the ciphertext policies of our system are sufficiently expressive and overcome the restriction
that ``each attribute is used only once\'\' that constrained previous constructions. Besides versatility, another goal of our work is to increase efficiency and practicality. As a result,
we use the significantly faster prime order bilinear groups rather than composite order groups. The construction is non-adaptively secure in the random oracle model under a non-interactive q-type assumption, similar to one used in prior works. Our work
extends existing ``program-and-cancel\'\' techniques to prove security and introduces two new techniques of independent interest for other ABE constructions. We provide an implementation and some benchmarks of our construction in Charm, a programming framework developed for rapid prototyping of cryptographic primitives.
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