End-to-End Encrypted Messaging

A book written by Rolf Oppliger and published in 2020 by Artech House in the Information Security and Privacy Series (visit the Insider Blog)

ISBN: 978-1-63081-732-9

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Aims and Scope

This book provides a comprehensive treatment of end-to-end encrypted (E2EE) messaging as it is currently used on the Internet. It starts with OpenPGP and S/MIME, elaborates on OTR, and then mainly addresses Signal, the use of Signal in WhatsApp and a few other E2EE messengers (e.g., Viber, Wire, and Rot), as well as E2EE messengers that are widely deployed but don’t use the Signal protocol, such as iMessage, Wickr, Threema, and Telegram. The book also outlines privacy issues and standardization.

Target Audience

The book is intended for anyone who wants to understand what end-to-end encrypted (E2EE) messaging is and how it is implemented on the Internet. It speaks to theorists and practitioners.

Table of Contents

1. Introduction
2. Internet Messaging
3. Cryptographic Techniques
4. Secure and E2EE Messaging
5. OpenPGP
7. Evolutionary Improvements
8. OTR
9. Signal
10. WhatsApp
11. Other E2EE Messengers
12. Privacy Issues
13. Conclusions and Outlook
Abbreviations and Acronyms
About the Author


Errata List

  • Page 274, line 13 (2nd paragraph, 1st sentence): AES-CTR decryption of the message must occur before M_i can be verified according to equation (11.1). Consequently, the order of the clauses must be changed.
  • Page 292, 8th line from the bottom: The first word should be “where” instead of “whereas.”


  • On November 5, 2020, I will teach a course on E2EE messaging on the Internet in the eSECURITY Academy.

    Additional Material