Authentication and Key Management Automation in Decentralized Secure Email and Messaging via Low-entropy Secrets

Itzel Vazquez Sandoval, Arash Atashpendar, Gabriele Lenzini

2020

Abstract

We revisit the problem of entity authentication in decentralized end-to-end encrypted email and secure messaging to propose a practical and self-sustaining cryptographic solution based on password-authenticated key exchange (PAKE). This not only allows users to authenticate each other via shared low-entropy secrets, e.g., memorable words, without a public key infrastructure or a trusted third party, but it also paves the way for automation and a series of cryptographic enhancements; improves security by minimizing the impact of human error and potentially improves usability. First, we study a few vulnerabilities in voice-based out-of-band authentication, in particular a combinatorial attack against lazy users, which we analyze in the context of a secure email solution. Next, we propose solving the problem of secure equality test using PAKE to achieve entity authentication and to establish a shared high-entropy secret key. Our solution lends itself to offline settings, compatible with the inherently asynchronous nature of email and modern messaging systems. The suggested approach enables enhancements in key management such as automated key renewal and future key pair authentications, multi-device synchronization, secure secret storage and retrieval, and the possibility of post-quantum security as well as facilitating forward secrecy and deniability in a primarily symmetric-key setting. We also discuss the use of auditable PAKEs for mitigating a class of online guess and abort attacks in authentication protocols.

Paper Citation

in Harvard Style

Vazquez Sandoval I., Atashpendar A. and Lenzini G. (2020). Authentication and Key Management Automation in Decentralized Secure Email and Messaging via Low-entropy Secrets.In Proceedings of the 17th International Joint Conference on e-Business and Telecommunications - Volume 3: SECRYPT, ISBN 978-989-758-446-6, pages 167-179. DOI: 10.5220/0009834001670179

in Bibtex Style

@conference{secrypt20,
author={Itzel Vazquez Sandoval and Arash Atashpendar and Gabriele Lenzini},
title={Authentication and Key Management Automation in Decentralized Secure Email and Messaging via Low-entropy Secrets},
booktitle={Proceedings of the 17th International Joint Conference on e-Business and Telecommunications - Volume 3: SECRYPT,},
year={2020},
pages={167-179},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0009834001670179},
isbn={978-989-758-446-6},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 17th International Joint Conference on e-Business and Telecommunications - Volume 3: SECRYPT,
TI - Authentication and Key Management Automation in Decentralized Secure Email and Messaging via Low-entropy Secrets
SN - 978-989-758-446-6
AU - Vazquez Sandoval I.
AU - Atashpendar A.
AU - Lenzini G.
PY - 2020
SP - 167
EP - 179
DO - 10.5220/0009834001670179