Can Johnny build a protocol? Co-ordinating developer and user intentions for privacy-enhanced secure messaging protocols

As secure messaging protocols face increasingly widespread deployment, differences between what developers “believe” about user needs and the actual needs of real-existing users could have an impact on the design of future technologies. In the domain of secure messaging, the sometimes subtle choices made by protocol designers tend to elude the understanding of users, including high-risk activists. We’ll overview some common protocol design questions facing developers of secure messaging protocols and test the competing understandings of these questions using STS-inspired interviews with the designers of popular secure messaging protocols ranging from older protocols like PGP and XMPP+OTR to newer unstandardized protocols used in Signal and Briar. Far from taking users as a homogeneous and undifferentiated mass, we distinguish between the low-risk users that appear in most usability studies (such as university students in the USA and Europe) and high-risk activist userbases in countries such as Ukraine and Egypt where securing messages can be a matter of life or death.

[1]  Nikita Borisov,et al.  Off-the-record communication, or, why not to use PGP , 2004, WPES '04.

[2]  Rob Miller,et al.  Johnny 2: a user test of key continuity management with S/MIME and Outlook Express , 2005, SOUPS '05.

[3]  Cas J. F. Cremers,et al.  On Post-compromise Security , 2016, 2016 IEEE 29th Computer Security Foundations Symposium (CSF).

[4]  Michelle L. Mazurek,et al.  You are Not Your Developer, Either: A Research Agenda for Usable Security and Privacy Research Beyond End Users , 2016, 2016 IEEE Cybersecurity Development (SecDev).

[5]  Morgan Meyer.  The Rise of the Knowledge Broker , 2010 .

[6]  J. Doug Tygar,et al.  Why Johnny Can't Encrypt: A Usability Evaluation of PGP 5.0 , 1999, USENIX Security Symposium.

[7]  Hugo Krawczyk,et al.  Secure off-the-record messaging , 2005, WPES '05.

[8]  Audun Jøsang,et al.  Security in Mobile Communications: Challenges and Opportunities , 2003, ACSW.

[9]  H. M. Collins,et al.  The Third Wave of Science Studies , 2002, Science, Technology, and Society.

[10]  Ian Goldberg,et al.  Improved user authentication in off-the-record messaging , 2007, WPES '07.

[11]  M. Angela Sasse,et al.  Users are not the enemy , 1999, CACM.

[12]  Jörg Schwenk,et al.  How Secure is TextSecure? , 2016, 2016 IEEE European Symposium on Security and Privacy (EuroS&P).

[13]  Markus Huber,et al.  When SIGNAL hits the Fan: On the Usability and Security of State-of-the-Art Secure Mobile Messaging , 2016 .

[14]  Ian Goldberg,et al.  A user study of off-the-record messaging , 2008, SOUPS '08.

[15]  Ian Goldberg,et al.  SoK: Secure Messaging , 2015, 2015 IEEE Symposium on Security and Privacy.

[16]  Jakob Jakobsen,et al.  On the CCA (in)Security of MTProto , 2015, SPSM@CCS.

[17]  Matthew Green,et al.  Developers are Not the Enemy!: The Need for Usable Security APIs , 2016, IEEE Security & Privacy.

[18]  Don Davis,et al.  Defective Sign & Encrypt in S/MIME, PKCS#7, MOSS, PEM, PGP, and XML , 2001, USENIX Annual Technical Conference, General Track.

[19]  S. Freytag.  Image And Logic A Material Culture Of Microphysics , 2016 .

[20]  J. Krige.  How Users Matter: The Co-Construction of Users and Technology , 2006 .

[21]  Matthew Smith,et al.  Helping Johnny 2.0 to encrypt his Facebook conversations , 2012, SOUPS.