## Cryptology ePrint Archive: Report 2017/441

New Approach to Practical Leakage-Resilient Public-Key Cryptography

Suvradip Chakraborty and Janaka Alawatugoda and C. Pandu Rangan

Abstract: We present a new approach to construct several leakage-resilient cryptographic primitives, including public-key encryption (PKE) schemes, authenticated key exchange (AKE) protocols and low-latency key exchange (LLKE) protocols. To this end, we develop a new primitive called \emph{leakage-resilient non-interactive key exchange} (LR-NIKE). We introduce a new generic security model for LR-NIKE protocols, which can be instantiated in both bounded-and-continuous-memory leakage setting. We then show a secure construction of LR-NIKE protocol in the bounded-memory leakage setting, that achieves an optimal leakage rate, i.e., $1- o(1)$. We then show how to construct the aforementioned leakage-resilient primitives from such a LR-NIKE. %Our approach not only gives an alternate design strategy of these leakage-resilient primitives, but also admits more efficient constructions than the state-of-the-art construction of some of these primitives, like public-key encryption. In particular,

\begin​{enumerate} \item[$\bullet$] We show how to construct a leakage-resilient IND-CCA-2-secure PKE scheme in the bounded-memory leakage setting, from LR-NIKE protocol. Our construction differs from the state-of-the-art constructions of leakage-resilient IND-CCA-2-secure PKE, which use hash proof techniques to achieve leakage resiliency. Moreover, our transformation preserves the leakage-rate of the underlying LR-NIKE and admits more efficient construction than the previous such PKE constructions.

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\item[$\bullet$] We introduce a new leakage model for AKE protocols, in the bounded-memory leakage setting. We show how to construct a leakage-resilient AKE protocol starting from LR-NIKE protocol. %This gives new constructions of leakage-resilient AKE.

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\item[$\bullet$] We introduce the first-ever leakage model for LLKE protocols, in the bounded-memory leakage setting, and the first construction of such a leakage-resilient LLKE from LR-NIKE protocol. %Our work gives the first leakage security model for leakage-resilient LLKE and their construction. \end{enumerate}

Category / Keywords: leakage-resilient, public-key encryption, key exchange protocols

Date: received 20 May 2017, last revised 10 Jun 2017

Contact author: araliyaqut at gmail com

Available format(s): PDF | BibTeX Citation

Short URL: ia.cr/2017/441

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