(This post was written by a researcher in the Cryptography, Security, and Privacy (CrySP) lab at the University of Waterloo. The opinions expressed here do not necessarily reflect the opinions of other CrySP researchers or the university.)

Written: 2016-12-22 (Updated 2017-03-23)

Update (2016-12-29): After this page was originally posted, Wire sent us a response. We have updated this text to incorporate their clarifications. Each point now also includes a summary (written by us) of Wire's response. The original article text and Wire's full response are available in the response document.

Update 2 (2017-03-23): Wire recently updated their calling protocol to add end-to-end authentication and constant bitrate encoding. We will update this page shortly after examining the details.

Recently, the Wire secure messaging application has received increased attention from the media and the public. In the wake of the Snowden revelations, we have seen the release of many secure messaging platforms, each claiming to offer excellent security features. Unfortunately, it is often difficult to evaluate the truth of these claims. We have also seen multiple instances where users place their trust in flawed or outright broken systems based on word-of-mouth recommendations or shallow media endorsements.

Luckily, Wire has behaved responsibly in this respect. Unlike many of their competitors, they published security and privacy whitepapers explaining the operation of their system. Allowing a protocol to be openly evaluated by security researchers is an important part of building a secure system.

The design of the Wire protocol as described in the whitepapers is relatively good. However, there are a few problems with the system and its specification that cause or suggest security weaknesses. Most of these problems come from the description in the whitepapers—if the actual app avoids the problems, then the documentation is merely incomplete. These problems should not be too difficult to fix, but they should be addressed before users rely on Wire for protecting their communications.

Issues (roughly in order of decreasing severity):

The problems listed above weaken the security of Wire relative to competitors like Signal, but the problems are not insurmountable. The chat features offered by Wire have a very modern aesthetic that is very popular with users, and this makes Wire a very interesting offering. Users should be aware of these concerns before choosing to use Wire. While these problems are unaddressed, users should avoid using Wire audio/video calls for secure conversations, assume that Wire passwords could be silently compromised, treat the Wire application like a constantly updating web service rather than a semi-stable desktop application, and consider sandboxing Wire on sensitive systems.


Cryptography, Security, and Privacy Research Group
David R. Cheriton School of Computer Science
University of Waterloo
Waterloo, Ontario, Canada N2L 3G1
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