Cryptology ePrint Archive: Report 2012/224

Shorter Identity-Based Encryption via Asymmetric Pairings

Jie Chen and Hoon Wei Lim and San Ling and Huaxiong Wang and Hoeteck Wee

Abstract: We present efficient Identity-Based Encryption (IBE) under the Symmetric External Diffie-Hellman (SXDH) assumption in bilinear groups. In our IBE scheme, all parameters have constant numbers of group elements, and are shorter than those of previous constructions based on Decisional Linear (DLIN) assumption. Our construction uses both dual system encryption (Waters, Crypto '09) and dual pairing vector spaces (Okamoto and Takashima, Pairing '08, Asiacrypt '09). Specifically, we show how to adapt the recent DLIN-based instantiation of Lewko (Eurocrypt '12) to the SXDH assumption. To our knowledge, this is the first work to instantiate either dual system encryption or dual pairing vector spaces under the SXDH assumption. Furthermore, our work could be extended to many other Functional Encryption. Particularly, we show how to instantiate our framework to Inner Product Encryption (IPE) and Key-Policy Functional Encryption (KP-FE). All parameters of our constructions are shorter than those of DLIN-based constructions.

Category / Keywords: public-key cryptography / Identity-Based Encryption, Dual System Encryption, Signatures, Asymmetric Pairings

Publication Info: A preliminary version of this paper appeared in the 5th International Conference on Pairing-Based Cryptography (Pairing 2012).

Date: received 23 Apr 2012, last revised 25 Mar 2013

Contact author: s080001 at e ntu edu sg;hoeteck@gwu edu

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Version: 20130325:111413 (All versions of this report)

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