Cryptology ePrint Archive: Report 2014/772

Fully Secure and Succinct Attribute Based Encryption for Circuits from Multi-linear Maps

Nuttapong Attrapadung

Abstract: We propose new fully secure attribute based encryption (ABE) systems for polynomial-size circuits in both key-policy and ciphertext-policy flavors. All the previous ABE systems for circuits were proved only selectively secure. Our schemes are based on asymmetric graded encoding systems in composite-order settings. The assumptions consist of the Subgroup Decision assumptions and two assumptions which are similar to Multi-linear Decisional Diffie-Hellman assumption (but more complex) and are proved to hold in the generic graded encoding model. Both of our systems enjoy succinctness: key and ciphertext sizes are proportional to their corresponding circuit and input string sizes. Our ciphertext-policy ABE for circuits is the first to achieve succinctness, and the first that can deal with unbounded-size circuits (even among selectively secure systems). We develop new techniques for proving co-selective security of key-policy ABE for circuits, which is the main ingredient for the dual-system encryption framework that uses computational arguments for enforcing full security.

Category / Keywords: public-key cryptography / Attribute-based encryption for circuits, Full security, Multi-linear maps, Dual system encryption, Ciphertext-policy, Key-policy, Succinctness

Date: received 30 Sep 2014

Contact author: n attrapadung at aist go jp

Available format(s): PDF | BibTeX Citation

Version: 20141001:060559 (All versions of this report)

Short URL: ia.cr/2014/772

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