You might assume that people in the most oppressive regimes wouldn't use the Tor anonymity network because of severe restrictions on technology or communication. On the other hand, you might think that people in the most liberal settings would have no immediate need for Tor. A new paper shows that Tor usage is in fact highest at both these tips of the political spectrum, peaking in the most oppressed and the most free countries around the world.
"There is evidence to suggest that at extreme levels of repression, Tor does provide a useful tool to people in those circumstances to do things that they otherwise would not be able to do," Eric Jardine, research fellow at the Centre for International Governance Innovation (CIGI), a Canadian think-tank, told Motherboard in a phone call. Jardine is the author of the new paper, recently published in peer-reviewed journal New Media & Society.
Jardine analysed data from 157 countries, stretching from 2011 to 2013. That information included a rating for a country's political repression, derived from assessments made by US-based research group Freedom House, and metrics for Tor usage, sourced from the Tor Project's own figures.
"Controlling for other relevant factors, political repression does drive usage of the Tor network"
Jardine included data for use of both Tor relays, which are nodes of the network users typically route their traffic through, and bridges, which are essentially non-public relays designed to be used in censorship-heavy countries that might block access to normal relays. He also considered a country's internet penetration rate, intellectual property rights regime, wealth, secondary education levels, and openness to foreign influences.
"The results show that, controlling for other relevant factors, political repression does drive usage of the Tor network," Jardine writes.
Bridges had the strongest association with political repression. "Moving from a country like Burkina Faso (political repression equals 8) to a country like Uzbekistan (political repression equals 14) results in an increase of around 212.58 Tor bridge users per 100,000 Internet users per year," the paper reads.
There was also a "statistically significant" relationship between a regime's political context and the use of Tor overall, Jardine adds.
Interestingly, however, it's not just harsh regimes that have a higher Tor usage. Countries on the lower end of the political repression spectrum also showed significant use. It was countries in the middle, ranked neither as strictly authoritarian regimes or free democracies, that had the lowest number of people connecting to Tor.
This might run counter to some people's intuition; wouldn't liberal democracies have little need for Tor?
"But because it's dual-use, you start to see a different pattern," Jardine said, meaning that Tor is not just used to circumvent censorship in oppressive regimes, for example. Instead, the technology could be to protect privacy, or for criminal purposes. (It's worth remembering that the study looked at data largely before the fallout of Edward Snowden's June 2013 revelations).
Why Tor usage peaks at the extremes of the political spectrum is less clear. Jardine hypothesises that it may be connected to a country's political need for such tools, such as circumventing censorship, but also the increased opportunity for their use—for example, in the US, Tor can be used easily without major consequence. Finding out the reasons for the trend are, however, beyond the scope of this study.
Tor, and the related technology of hidden services, can polarise discussions, with supporters often refusing to acknowledge criminal applications, and critics ignoring positive aspects. In a debate that is often overshadowed by emotions and feverish media coverage, having empirical data and analysis on the use of anonymity technology can only be beneficial.