Ciphertext-Policy Delegatable Hidden Vector Encryption and Its Application

Mitsuhiro HATTORI
Takashi ITO
Takumi MORI
Yusuke SAKAI
Kazuo OHTA

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E96-A    No.1    pp.53-67
Publication Date: 2013/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E96.A.53
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Public Key Based Protocols
hidden vector encryption,  searchable encryption,  pairing-based cryptography,  

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We propose a new hidden vector encryption (HVE) scheme that we call a ciphertext-policy delegatable hidden vector encryption (CP-dHVE) scheme. Several HVE schemes have been proposed and their properties have been analyzed extensively. Nonetheless, the definition of the HVE has been left unchanged. We therefore reconsider it, and point out that the conventional HVE should be categorized as the key-policy HVE, because the vectors corresponding to the secret keys can contain wildcards (which specify an access policy) whereas those corresponding to the ciphertexts cannot contain them. We then formalize its dual concept, the ciphertext-policy HVE, and propose a concrete scheme. Then, as an application of our scheme, we propose a public-key encryption with conjunctive keyword search scheme that can be used in the hierarchical user systems. Our scheme is novel in that the ciphertext size grows logarithmically to the number of uses in the system, while that of a conventional scheme grows linearly.