Cryptography done right has become important as the impacts of poor implementations are increasingly felt by journalists, whistleblowers and political activists around the world.
Nik Unger and Dr. Ian Goldberg at the University of Waterloo have been working on improving cryptography for messaging. Cryptography is designed to provide a level of security for messages beyond just passing the messages in plain sight. Encrypting messages provides a level of protection against people reading it but it also provides other features. Using systems such as PGP it provides for a level of assurance as to who you are communicating with. Although there are situations where this can be a good thing, it is also a step down from passing unencrypted messages because it provable links a person with a message, something that messages did not do. Losing this deniability is a problem if it is not expected and in a lot of instances there is no benefit to proving the originator of a message. To overcome this issue, the team at the University of Waterloo have been developing approaches to Off-The-Record (OTR) messaging.
The paper “Improved Strongly Deniable Authenticated Key Exchanges for Secure Messaging” introduces three protocols for Deniable Authenticated Key Exchange (DAKE); DAKEZ, ZDH, and XZDH. These new approaches provide the benefits of permitting additional security measures such allowing the addition of seeding forged messages into a message stream to increase the level of doubt about the author of a message and allowing the system to provide deniability on asynchronous communications. If you are working on developing communications platform or integrating chat functionality for a system then you should read this paper.
Nik Unger will be presenting this work at the Privacy Enhancing Technology Symposium in Barcelona, Spain this July 24-27. https://petsymposium.org. If you are at that event I recommend taking the time to speak with Mr Unger.
Unger, N., & Goldberg, I. (2018). Improved Strongly Deniable Authenticated Key Exchanges for Secure Messaging. Proceedings on Privacy Enhancing Technologies, 2018(1), 21-66.