Volume 8 - Issue 4
Expressive Ciphertext-Policy Attribute-Based Encryption with Fast Decryption
- Hikaru Tsuchida
NEC Corporation, Kanagawa, 211-8666, Japan
h-tsuchida@bk.jp.nec.com
- Takashi Nishide
Faculty of Engineering, Information and Systems, University of Tsukuba, Ibaraki, 305-8573, Japan
nishide@risk.tsukuba.ac.jp
- Eiji Okamoto
Faculty of Engineering, Information and Systems, University of Tsukuba, Ibaraki, 305-8573, Japan
okamoto@risk.tsukuba.ac.jp
Keywords: Attribute-Based Encryption, Non-monotone Access Structure, Fast Decryption
Abstract
Attribute-Based Encryption (ABE) is a cryptosystem which supplies access control for an encrypted
data in a cloud storage and has been actively studied. However, in the ABE system, a receiver needs
much time to decrypt an encrypted data. It is because the cost of pairing operations for decryption
becomes heavy linearly with the size of an access structure specified for ciphertexts. Due to
this, the construction of ABE is required to reduce the number of pairing operations and achieve
expressiveness of an access structure simultaneously. In this paper, we propose a new construction
of ciphertext-policy ABE supporting general predicates with a constant number of pairing operations
for decryption. We also prove that our construction achieves new security notion which we
introduce, restricted-selectively payload-hiding security under the q-type decisional bilinear Deiffie-
Hellman assumption.