Encrypted MultiChannel Communication (EMC2): Johnny Should Use Secret Sharing

Gowri R. Chandran; Kilian Demuth; Kasra Edalatnejad; Sebastian Linsner; Christian Reuter; Thomas Schneider

Paper 2024/1407

Encrypted MultiChannel Communication (EMC2): Johnny Should Use Secret Sharing

Gowri R. Chandran

, Technical University of Darmstadt

Kilian Demuth

, Technical University of Darmstadt

Kasra Edalatnejad

, Technical University of Darmstadt

Sebastian Linsner

, Technical University of Darmstadt

Christian Reuter

, Technical University of Darmstadt

Thomas Schneider

, Technical University of Darmstadt

Abstract

Nowadays, the problem of point-to-point encryption is solved by the wide adaptation of protocols like TLS. However, challenges persist for End-to-End Encryption (E2EE). Current E2EE solutions, such as PGP and secure messengers like Signal, suffer from issues like 1) low usability, 2) small user base, 3) dependence on central service providers, and 4) susceptibility to backdoors. Concerns over legally mandated backdoors are rising as the US and EU are proposing new surveillance regulations requiring chat monitoring. We present a new E2EE solution called Encrypted MultiChannel Communication, based on n-out-of-n secret sharing. EMC2 splits messages into multiple secret shares and sends them through independent channels. We show that multiple independent channels exist between users and EMC2 provides E2EE with no single point of trust, no setup, and is understandable by the general public. Our solution complements existing tools and aims to strengthen the argument against legally enforced backdoors by demonstrating their ineffectiveness.

Metadata

Available format(s): PDF
Category: Applications
Publication info: Published elsewhere. WPES 2024
DOI: 10.1145/3689943.3695051
Keywords: End-to-End Encryption secret sharing
Contact author(s): chandran @ encrypto cs tu-darmstadt de
demuth @ peasec tu-darmstadt de
edalat @ encrypto cs tu-darmstadt de
linsner @ peasec tu-darmstadt de
reuter @ peasec tu-darmstadt de
schneider @ encrypto cs tu-darmstadt de
History: 2024-09-11: approved; 2024-09-09: received; See all versions
Short URL: https://ia.cr/2024/1407
License: CC BY

BibTeX

@misc{cryptoeprint:2024/1407,
      author = {Gowri R. Chandran and Kilian Demuth and Kasra Edalatnejad and Sebastian Linsner and Christian Reuter and Thomas Schneider},
      title = {Encrypted {MultiChannel} Communication ({EMC2}): Johnny Should Use Secret Sharing},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/1407},
      year = {2024},
      doi = {10.1145/3689943.3695051},
      url = {https://eprint.iacr.org/2024/1407}
}