Archived research project

DigiTally

An offline mobile payment scheme designed for poor or unavailable network connectivity, developed as part of my doctoral research at the University of Cambridge.

Two mobile phones demonstrating DigiTally

DigiTally is an overlay payment scheme for mobile phones. It enables two people to make a payment by copying short strings of numbers between their phones, without requiring smartphones or a live network connection. Either phone can upload the transaction later when connectivity becomes available.

The project explored how mobile payments could be extended to areas with poor or intermittent connectivity while also reducing marginal network costs. The work developed and evaluated a human-usable protocol for constrained offline environments and formed part of my PhD research on resilient payment systems.

The research was supported by a Bill & Melinda Gates Foundation Grand Challenges Explorations grant focused on financial inclusion.

  • DigiTally: Piloting Offline Payments for Phones

    SOUPS 2017 paper and presentation. PaperSlides
  • SMAPs: Short Message Authentication Protocols

    Security Protocols XXIV. PaperDiscussion
  • Mobile payments under poor network conditions

    Public lecture with Ross Anderson, Strathmore University, Nairobi, 29 August 2016. Slides
  • Technology for the Bottom Billion Workshop

    Cambridge, 10 June 2016. Slides
  • Is it practical to build a truly distributed payment system?

    CCS 2016 keynote by Ross Anderson, Vienna, 26 October 2016. Slides