Iran is flexing its internet censorship muscles once again. This time, the targets are precisely those circumvention tools that help Iranians get around what some refer to as the Filternet or Great Firewall of Persia.
The biggest victim appears to be Tor, the popular software tool that anonymizes web traffic and also allows its users to get around censorship. The number of Tor users has been dropping steadily inside Iran since February 24. At that point, more than 40,000 Iranians were using the network, the highest number since October of last year, according to Tor internal metrics.
As of Thursday, the number of users is down to roughly 32,000.
For Iranian internet freedom activists, this is a cause for concern. In the country, large Western social networks like Twitter and Facebook have been blocked for years. The only way Iranian can access them is using circumvention tools, although the regime has tried to limit their use as well. For example, Iran has a long history of clampdowns on Tor.
Nariman Gharib, an Iranian researcher based in London, said that nobody knows exactly why this is happening now, but he's afraid this a bad omen for digital rights in Iran.
"They are developing or changing the infrastructure of internet censorship," he told Motherboard.
Gharib said he's convinced this is a sign of improved censorship capabilities because there's no other reason to crack down on these tools.
"They are developing or changing the infrastructure of internet censorship."
"If you have that ability to block access to Tor or other tools […] why wouldn't you do it in the past?" he said. "Something has changed—it's obvious, because there is no protest, no crisis in Iran, nothing. "
The Tor Project, which develops and maintains Tor, did not immediately respond to Motherboard's request for comment. Tor has been targeted in other countries as well lately. Russia has recently reiterated its intention to block Tor completely, and Belarus just banned Tor.
Amir Habibzadeh, an apps and software developer who lives in Tehran, told Motherboard that "all Iranians have these issues, but lately it's getting worse."
Habibzadeh said he started having problems using Tor, as well as other Virtual Private Networks (VPNs) around February 21, but some people have more or less issues depending on their internet service providers. Only Psiphon, a VPN specifically designed to get around censorship in countries like Iran or China, is working well, he said.
It's unclear if this crackdown on circumvention tools is part of a larger trend against digital rights in the country. But the Iranian government, and particularly the Iran's Revolutionary Guards Corps' (IRGC), which is under the control of Iran's Grand Ayatollah Ali Khamenei, has been very active in cyberspace lately.
"What they are doing it trying to spread fear between Iranian users."
Last month, the IRGC announced that it had arrested 12 Iranian Facebook users for "spreading corruption, and [carrying out a] mission to change family lifestyles."
This week, the IRGC's Cyber Security Command's Center for the Investigation of Organized Crimes, said that it's been monitoring 8 million Iranian Facebook users through a new surveillance project called "Operation Spider."
The operation's goal is to stop the spread of "pornographic and immoral" content, and "mass distribution" of rumors on the social network, according to a statement by the IRGC.
"[Facebook] is trying to push its users toward immoral content via its suggestion system, by making them choose harmful, decadent and obscene content over beneficial and educational subject matter," the IRGC said.
In light of all these events, Gharib said Iranians should be worried.
"What they are doing is trying to spread fear between Iranian users," he told Motherboard. "The only place you can read and engage with other people widely and freely is on social media websites. Now people are scared because they face arrest by IRGC."