Cryptology ePrint Archive: Report 2019/845

A Reaction Attack against Cryptosystems based on LRPC Codes

Simona Samardjiska and Paolo Santini and Edoardo Persichetti and Gustavo Banegas

Abstract: Rank metric is a very promising research direction for code-based cryptography. In fact, thanks to the high complexity of generic decoding attacks against codes in this metric, it is possible to easily select parameters that yield very small data sizes. In this paper we analyze cryptosystems based on Low-Rank Parity-Check (LRPC) codes, one of the classes of codes that are efficiently decodable in the rank metric. We show how to exploit the decoding failure rate, which is an inherent feature of these codes, to devise a reaction attack aimed at recovering the private key. As a case study, we cryptanalyze the recent McNie submission to NIST’s Post-Quantum Standardization process. Additionally, we provide details of a simple implementation to validate our approach.

Category / Keywords: public-key cryptography / Rank-based cryptography, Code-based cryptography, LRPC cryptosystems, reaction attacks, decryption failures

Original Publication (with minor differences): Latincrypt 2019

Date: received 19 Jul 2019

Contact author: simonas at cs ru nl

Available format(s): PDF | BibTeX Citation

Version: 20190719:135125 (All versions of this report)

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