CNN  — 

As protesters took to the streets of Iran following the death in detention of Mahsa Amini, a 22-year-old woman apprehended for apparently not wearing her hijab properly, videos of the uprising began to flood the internet.

Clips of students tearing up pictures of Iran’s Supreme Leader in northern Iran. Photos of women removing their hijab in Iran’s capital, Tehran. Videos of protesters marching down the streets of the capital with their fists in the air.

The outpouring of anger following Amini’s death was visible to the world.

But then it went dark as WhatsApp, Signal, Viber, Skype, and even Instagram, one of the last remaining social media apps to be usable, were blocked.

Internet shutdowns aren’t new in Iran, often accompanying periods of unrest and dissent. The most severe crackdown was in 2019, during which more than 100 protesters were killed and the internet was cut off for 12 days, according to Amnesty International.

Activists in Iran say that the primary purpose of the shutdowns is to disrupt communication among people organizing protests on the ground and stifle dissent.

“They don’t want you to be able to communicate with your friends, with your family, with your colleagues, because simply if you’re going to basically create a group […] you’re going to be more effective in the way that you are doing protest,” Amir Rashidi, director of digital rights and security at human rights organization Miaan Group, told CNN.

As a result of these frequent blackouts, tech-savvy Iranians have learned increasingly to rely on more advanced tools like VPNs or Tor network as workarounds to stay connected. But even these are now being restricted by authorities and are therefore far from reliable. “I can hardly get in touch with my friends because we can’t always get connected to VPNs,” 22-year-old Ali, whose name CNN changed because he fears for his safety, told CNN via an encrypted ProtonMail conversation.

A VPN, or virtual private network, encrypts the user’s traffic and connects it to a remote server, protecting the data and activity; Tor is an open-source network which allows anonymous web browsing; ProtonMail is an end-to-end encrypted email service.

“This time they are not just limiting the internet,” Ali added. “They have removed WhatsApp and Instagram from local app stores, they have blocked our connection to Google Play store and App Store so we can’t download any VPN or social media apps […] they do this so protesters can’t connect to each other and can’t share news on social media, the high censorship starts from 4pm to 11:59pm, sometimes we have issues even for calling each other!”

Another user, 18-year-old Nima, whose name CNN changed because he fears for his safety, told CNN there were no messaging apps that work in Iran right now without using VPNs, “The government is blocking VPNs right now, one by one. Our accessibility is getting limited each day. We are hardly able to know