The number of websites being censored in Saudi Arabia doubled a couple of weeks after Washington Post journalist Jamal Khashoggi was killed in the country’s consulate in Istanbul, according to an initiative that tracks internet censorship. While the increased censorship is not surprising, the results show how skillful automated tracking has become at sniffing out repression.

Roya Ensafi, who leads the Censored Planet project, says it detected the sharp increase in censorship activity when it ran an automated scan on October 16. That was the day after Saudi and Turkish officials had conducted a joint inspection of the consulate, which Khashoggi entered a couple of weeks earlier to get a marriage license.

Ensafi’s team runs these scans twice a week in more than 170 countries. She says the October scan showed that foreign news services such as Fox News, the Los Angeles Times, and the Canadian Broadcasting Corporation were suddenly being blocked. Although the interference has since diminished for some sites, access to the Times’ website and arabnews.com, an English-language daily in Saudi Arabia, is still being restricted.

Roya Ensafi of the Censored Planet project Joseph Xu, Michigan Engineering

Censored Planet, which was launched in August at the University of Michigan, is one of a number of initiatives that track online censorship, including the University of Toronto’s Citizen Lab and the Open Observatory of Network Interference (OONI). Some services, like OONI, rely on thousands of volunteers living under authoritarian regimes to run code that checks for crackdowns and then upload the results to their servers.

Ensafi, who grew up in Iran, has developed a way of monitoring censorship in repressive regimes without having to rely on volunteers, who could be subject to reprisals. Censored Planet’s software searches the internet for publicly available servers at places like universities or companies providing internet access in the countries it monitors. It then instructs these machines to conduct several different scans to check if any of the approximately 2,000 websites it tracks are being blocked.

One scan looks to see if censors are blocking access to internet protocol (IP) addresses that are associated with the websites Censored Planet monitors. Another checks for manipulation of servers running the domain name system, which helps route traffic to correct destinations over the internet. Regimes can tamper with this by, for example, redirecting requests for certain websites to incorrect IP addresses. The third scan looks for keyword blocking, which involves censors monitoring network traffic for certain sensitive words and then blocking traffic containing them.

In e-mailed comments to MIT Technology Review, Arturo Filastò, a cofounder of OONI, says that its approach shows how actual users are experiencing censorship on their devices, which Censored Planet can’t do. He also says he isn’t aware of any volunteer who has gotten into trouble for running software that looks for evidence of censorship. OONI takes care to warn people of potential risks and works closely with local lawyers to keep an eye on emerging threats.

Nevertheless, Filastò welcomes Censored Planet’s approach and says it’s complementary to OONI’s because it can use remote testing to track much greater numbers of websites. As his organization’s software runs on bandwidth paid for by its volunteers, it has to limit the number of sites being tracked. Both services publish their findings openly so that other researchers can use them.