IACR News item: 27 May 2014
Dennis Hofheinz
ePrint ReportIn this paper, we construct the first fully secure CPRF without any of the above restrictions. Concretely, we support ``bit-fixing\'\' constrained keys that hardwire an arbitrary subset of the input bits to fixed values, we support exponentially large input spaces, and our security reduction is polynomial. We require very heavyweight tools: we assume multilinear maps, indistinguishability obfuscation, and our proof is in the random oracle model. Still, our analysis is far from tautological, and even with these strong building blocks, we need to develop additional techniques and tools.
As a simple application, we obtain the first adaptively secure non-interactive key exchange protocols for large user groups.
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