Cryptology ePrint Archive: Report 2018/508

Cost-Effective Private Linear Key Agreement With Adaptive CCA Security from Prime Order Multilinear Maps and Tracing Traitors

Mriganka Mandal and Ratna Dutta

Abstract: Private linear key agreement (PLKA) enables a group of users to agree upon a common session key in a broadcast encryption (BE) scenario, while traitor tracing (TT) system allows a tracer to identify conspiracy of a troop of colluding pirate users. This paper introduces a key encapsulation mechanism in BE that provides the functionalities of both PLKA and TT in a unified cost-effective primitive. Our PLKA based traitor tracing offers a solution to the problem of achieving full collusion resistance property and public traceability simultaneously with significant efficiency and storage compared to a sequential improvement of the PLKA based traitor tracing systems. Our PLKA builds on a prime order multilinear group setting employing indistinguishability obfuscation (iO) and pseudorandom function (PRF). The resulting scheme has a fair communication, storage and computational efficiency compared to that of composite order groups. Our PLKA is adaptively chosen ciphertext attack (CCA)-secure and based on the hardness of the multilinear assumption, namely, the Decisional Hybrid Diffie-Hellman Exponent (DHDHE) assumption in standard model and so far a plausible improvement in the literature. More precisely, our PLKA design significantly reduces the ciphertext size, public parameter size and user secret key size. We frame a traitor tracing algorithm with shorter running time which can be executed publicly.

Category / Keywords: public-key cryptography / broadcast encryption, private linear key agreement, traitor tracing, multilinear maps, indistinguishability obfuscation

Date: received 25 May 2018

Contact author: mriganka_mandal at maths iitkgp ernet in

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Version: 20180526:142736 (All versions of this report)

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