An anonymous Transit Ticket system solves the privacy-related issues of Contact Tracing App

1/ Contact Tracing in the Real World

Contact Tracing in the Real World April 12th, 2020 Ross Anderson

“Fourth, the public health authorities need geographical data for purposes other than contact tracing”, Ross Anderson,

“Fifth, a voluntary app operated by anonymous actors is wide open to trolling”

“Seventh, on the systems front, decentralised systems are all very nice in theory but are a complete pain in practice as they’re too hard to update”…

“I recognise the overwhelming force of the public-health arguments for a centralised system, but I also have 25 years’ experience of the NHS being incompetent at developing systems and repeatedly breaking their privacy promises when they do manage to collect some data of value to somebody else.”

2/ Public Place Location-based Prevention System

iBonus Limited believes the most effective way to tackle this problem is to use anonymous public transit smart cards and also to install dedicated terminals in public places such as a library, cinema, school, and gym to record where and when the people have visited.

When a person is reported as virus-infected by medical authorities, the system immediately puts all persons who appear in the same place at the same time as the confirmed patient in the past 14 days into an “Alert” list and transmits it to all terminals. The Alert list is valid from one day to fourteen days, depending on the date of contact.

The self-help terminal gives a friendly alert to susceptible persons when they are entering public areas.


  • No privacy issue because the phone number will be converted to an irreversible ID and, in addition, people can use anonymous transit smart cards.
  • Big data of asymptomatic movement and asymptomatic infection growth is an index to measure if Covid19 spread is under control.
  • The location factor of a public gathering place will give a good preventive mechanism to reduce asymptomatic spread.
  • Make the public gathering place safer to visit and resume normal economic activities.


  • The private sector needs to buy a portable device at about USD 250. (The average cost of a thermometer gun is USD 100.)
  • The terminal is used for self-check. However, it may have a dispute if a person is not allowed to go into a facility.