## Cryptology ePrint Archive: Report 2016/1176

Leakage of Signal function with reused keys in RLWE key exchange

Jintai Ding and Saed Alsayigh and Saraswathy RV and Scott Fluhrer and Xiaodong Lin

Abstract: In this paper, we show that the signal function used in Ring-Learning with Errors (RLWE) key exchange could leak information to find the secret $s$ of a reused public key $p=as+2e$. This work is motivated by an attack proposed in \cite{cryptoeprint:2016:085} and gives an insight into how public keys reused for long term in RLWE key exchange protocols can be exploited. This work specifically focuses on the attack on the KE protocol in \cite{Ding} by initiating multiple sessions with the honest party and analyze the output of the signal function. Experiments have confirmed the success of our attack in recovering the secret.

Category / Keywords: RLWE, key exchange, post quantum, key reuse, active attacks

Original Publication (in the same form): 2017 IEEE ICC Conference Proceedings

Date: received 22 Dec 2016, last revised 4 Dec 2017

Contact author: jintai ding at gmail com;rvsaras86@gmail com

Available format(s): PDF | BibTeX Citation

Note: minor corrections

Short URL: ia.cr/2016/1176

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