Captchat: a messaging tool to frustrate ubiquitous surveillance

Paul Dunphy, Patrick Olivier, Johannes Schöning, James Nicholson

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

Abstract

There is currently a widespread uncertainty regarding the ability of citizens to control privacy online in the face of ubiquitous surveillance. This is a huge and complex societal problem. Despite the multi-faceted nature of the problem, we propose that HCI researchers can still make a positive contribution in this space through the design of technologies that support citizens to engage with issues of surveillance. In this paper we describe the design of a messaging application called Captchat. Captchat enables people to send everyday messages embedded into images, with the added ability to apply visual distortions to the message to resemble an online CAPTCHA. We propose the chief benefit would be that Captchat messages (with potentially "one-time" distortions) can increase the difficulty for algorithms to index private messages and necessitate the involvement of much more costly human labor in the surveillance process. We developed a prototype and conducted a user study; the results suggest that people were likely to create Captchat messages that were difficult to index for an OCR package but still easy to understand by humans, even without explicit instructions to interact 'securely' with the application. While more work is still required to understand the limitations of Captchat, we hope it can open discussion on how HCI researchers can respond to the challenges faced from ubiquitous surveillance.

Original languageEnglish
Title of host publicationSIGCHI/CHI 2015 - Extended Abstracts Publication of the 33rd Annual CHI Conference on Human Factors in Computing Systems
Subtitle of host publicationApril 18–23, 2015 Seoul, Republic of Korea
EditorsKori Inkpen, Woontack Woo
Place of PublicationNew York NY US
PublisherAssociation for Computing Machinery (ACM)
Pages639-646
Number of pages8
ISBN (Electronic)9781450331463, 9781450331456
DOIs
Publication statusPublished - 2015
Externally publishedYes
EventInternational Conference on Human Factors in Computing Systems 2015 - Seoul, Korea, Republic of (South)
Duration: 18 Apr 201523 Apr 2015
Conference number: 33rd
https://chi2015.acm.org/
https://dl.acm.org/doi/proceedings/10.1145/2702123 (Proceedings)

Conference

ConferenceInternational Conference on Human Factors in Computing Systems 2015
Abbreviated titleCHI 2015
CountryKorea, Republic of (South)
CitySeoul
Period18/04/1523/04/15
Internet address

Keywords

  • Captchat
  • Mobile messaging
  • Privacy
  • Ubiquitous surveillance

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