Summary
The 2018 International Symposium on Information Theory and Its Applications (ISITA2018)
2018
Session Number:We-AM-Poster
Session:
Number:We-AM-Poster.4
Attack on Multiple-Use Password Protected Secret Sharing
Taiyu Kamiyama, Yuta Ugaya, Keisuke Kodaira, Tomoharu Shibuya,
pp.494-494
Publication Date:2018/10/18
Online ISSN:2188-5079
DOI:10.34385/proc.55.We-AM-Poster.4
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Summary:
In order to enhance security and usability of conventional secret sharing, password protected secret sharing (PPSS) was invented. Recently, Nakahara et al. improved Ogata’s multiple-use PPSS (mPPSS), which protects multiple data by one password, by employing secure computation known as CSEC70 method in the user authentication. In this paper, we propose an attack on Nakahara’s mPPSS that presumes on a security hall in the adoption of CSEC70 method. Then, we show that the proposed attack enables an administrator of any server of the system to disclose the password of an arbitrary user in Nakahara’s mPPSS.