Attribute-Based Keyword Search from Lattices

Abstract

Attribute-based keyword search (ABKS) is a special case of public key encryption with keyword search (PEKS) which allows fine-grained control of the search ability and can be further categorized into key-policy ABKS (KP-ABKS) and ciphertext-policy ABKS (CP-ABKS). In a KP-ABKS (resp., CP-ABKS) scheme, a trapdoor that is associated with an access policy f (resp., an attributes string can only be used to search over ciphertexts that is associated with an attributes string (resp., an access policy f) if. As ABKS is very useful in the era of big data, many researchers have been devoted to design ABKS schemes with different features, but almost all the known schemes are based on the traditional number-theoretical assumptions such as Factoring or Discrete Logarithm, and thus are insecure against quantum adversaries. In this paper, we propose a lattice-based KP-ABKS scheme supporting circuit policy of any predetermined polynomial depth. Our scheme is provably secure against chosen keyword attacks and keyword guessing attacks under the DLWE and ISIS assumptions in the random oracle model. By using a universal circuit, our scheme can also be converted into a CP-ABKS scheme.