Encrypted messaging platform Telegram said it experienced a “powerful” cyberattack on Wednesday during massive protests in Hong Kong.
The attempted distributed denial of service, or DDoS, attack was aimed at flooding the app with so much traffic that it impaired normal service.
It originated from “IP addresses coming mostly from China,” Telegram founder Pavel Durov said on Twitter.
The impact was felt way beyond China.
“We’re currently experiencing a powerful DDoS attack, Telegram users in the Americas and some users from other countries may experience connection issues,” the company said in a tweet.
The attack “coincided in time with protests in Hong Kong,” where people were coordinating on Telegram groups, Durov said.
Hundreds of thousands of people have flooded the streets of Hong Kong this week, protesting against a controversial bill that would allow alleged criminals to be extradited to China.
They fear the bill will leave anyone in Hong Kong vulnerable to extradition by Chinese authorities for political reasons or business offenses, undermining the city’s legal system.
The former British colony was returned to China in 1997, when Beijing agreed to guarantee its semi-autonomous legal system and certain democratic freedoms for the next 50 years under a policy known as “one country, two systems.”
Hong Kong lawmakers were due to debate the extradition bill on Wednesday, but that debate was postponed after the latest round of protests resulted in violent clashes.
Many of the protesters have been using Telegram to coordinate their efforts. The messaging platform is designed to allow users to send messages protected by end-to-end encryption — the kind authorities can’t intercept easily.
CNN teams on the ground were told that the Telegram groups where people can get information about the Hong Kong protests range in number from hundreds of members to tens of thousands.
Telegram, which says it has 200 million users worldwide, has been used in protests before, including anti-government demonstrations in Iran last year.
The Berlin-based app uses two layers of encryption, allows users to remain anonymous, and claims to be faster and more secure than other messaging services.
It has come under fire in the past for being the preferred app of terrorists. Russia banned it last year after the company refused to provide encryption keys to the FSB, a Russian security agency.