IACR News item: 21 November 2012
Kwangsu Lee, Intae Kim, Seong Oun Hwang
ePrint ReportIn this paper, we first define two new security models of privacy preserving RPE: the strongly full-hiding security and the weakly full-hiding security. The strongly full-hiding security provides the full privacy of ciphertexts against outside and inside adversaries, but the weakly full-hiding security only provides the full privacy of ciphertexts against an outside adversary who cannot decrypt the challenge ciphertext. Next, we propose two general RPE constructions from any inner product encryption (IPE) schemes, and prove their security. This first RPE scheme provides the strongly full-hiding security, but the size of ciphertexts is proportional to the number of users in the system. The second RPE scheme improves the efficiency of the first RPE scheme such that the size of ciphertexts is sublinear and the decryption algorithm is efficient, but it provides the weakly full-hiding security.
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