IACR News item: 22 May 2014
Dan Boneh, Craig Gentry, Sergey Gorbunov, Shai Halevi, Valeria Nikolaenko, Gil Segev, Vinod
ePrint ReportWe construct our attribute-based system using a mechanism we call {\\em fully key-homomorphic encryption} which is a public-key system that lets anyone translate a ciphertext encrypted under a public-key~$\\vx$ into a ciphertext encrypted under the public-key~$(f(\\vx),f)$ of the same plaintext, for any efficiently computable~$f$. We show that this mechanism gives an ABE with short keys. Security is based on the subexponential hardness of the learning with errors problem.
We also present a second (key-policy) ABE, using multilinear maps, with short ciphertexts: an encryption to an attribute vector~$\\vx$ is the size of $\\vx$ plus $\\mathsf{poly}(\\secp,d)$ additional bits. This gives a reusable circuit garbling scheme where the size of the garbled input is short, namely the same as that of the original input, {\\em plus} a $\\mathsf{poly}(\\secp,d)$ factor.
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