State-free End-to-End Encrypted Storage and Chat Systems based on Searchable Encryption

Keita Emura, Ryoma Ito, Sachiko Kanamori, Ryo Nojima, Yohei Watanabe, Yohei Watanabe

2022

Abstract

Searchable symmetric encryption (SSE) has attracted significant attention because it can prevent data leakage from external devices, e.g., on clouds. SSE appears to be effective to construct such a secure system; however, it is not trivial to construct such a system from SSE in practice because other parts must be designed, e.g., user login management, defining the keyword space, and sharing secret keys among multiple users who usually do not have public key certificates. In this paper, we describe the implementation of two systems based upon the state-free dynamic SSE (DSSE) (Watanabe et al., ePrint 2021), i.e., a secure storage system (for a single user) and a chat system (for multiple users). In addition to the Watanabe et al. DSSE protocol, we employ a secure multipath key exchange (SMKEX) protocol (Costea et al., CCS 2018), which is secure against some classes of unsynchronized active attackers. It allows the chat system users without certificates to share a secret key of the DSSE protocol in a secure manner. To realize end-to-end encryption, the shared key must be kept secret; thus, we must consider how to preserve the secret on, for example, a user’s local device. However, this requires additional security assumptions, e.g., tamper resistance, and it seems difficult to assume that all users have such devices. Thus, we propose a secure key agreement protocol by combining the SMKEX and login information (password) that does not require an additional tamper-resistant device. Combining the proposed key agreement protocol and the underlying state-free DSSE protocol allow users who know the password to use the systems on multiple devices.

Paper Citation

in Harvard Style

Emura K., Ito R., Kanamori S., Nojima R. and Watanabe Y. (2022). State-free End-to-End Encrypted Storage and Chat Systems based on Searchable Encryption. In Proceedings of the 24th International Conference on Enterprise Information Systems - Volume 1: ICEIS, ISBN 978-989-758-569-2, pages 106-113. DOI: 10.5220/0011045200003179

in Bibtex Style

@conference{iceis22,
author={Keita Emura and Ryoma Ito and Sachiko Kanamori and Ryo Nojima and Yohei Watanabe},
title={State-free End-to-End Encrypted Storage and Chat Systems based on Searchable Encryption},
booktitle={Proceedings of the 24th International Conference on Enterprise Information Systems - Volume 1: ICEIS,},
year={2022},
pages={106-113},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0011045200003179},
isbn={978-989-758-569-2},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 24th International Conference on Enterprise Information Systems - Volume 1: ICEIS,
TI - State-free End-to-End Encrypted Storage and Chat Systems based on Searchable Encryption
SN - 978-989-758-569-2
AU - Emura K.
AU - Ito R.
AU - Kanamori S.
AU - Nojima R.
AU - Watanabe Y.
PY - 2022
SP - 106
EP - 113
DO - 10.5220/0011045200003179