How does ISIS communicate? A look at the Telegram messaging app the terrorist organization used

In the months following 9/11 it became clear al-Qaeda was using couriers to relay messages, among more obvious means of communication.

The courier method worked for years, keeping Osama Bin Laden out of the public eye for nearly a decade after the World Trade Center attacks, until CIA operatives tracked his personal messenger to a compound in Pakistan. The terrorist leader's archaic method of communication didn't leave a digital footprint, but it did leave him susceptible to outdated intel and the possibility that persons entrusted with hand-held information could be tracked.

Terrorist groups' ability to spread untraceable messages progressed with burgeoning online outlets. Gaming consoles because password-protected discussion forums where terrorists posed as "gamers," as did government agents trying to sniff them out.

They sent coded text messages, using metaphors like "architecture" to symbolize targeted buildings; accused al-Qaeda militant Abid Naseer reportedly used his so-called girlfriend's name, "Nadir," as code for blowing an England shopping center.

Most recently, they have begun using messaging apps. The same kind millions of American habitually use to send gifs and playful emoticons.

ISIS -the Islamic State of Iraq and Syria - is one of the more tech-savvy terrorist cells working out the Middle East and uses social media to extort cash, recruit radical Islamists, and flaunt hostages. They used the heavily-encrypted Telegram Messenger app to issue statements, including last Friday when they claimed responsibility for the Paris attacks that left at least 129 people dead.

On Wednesday, Telegram - which carries more than 60 million active users - told Twitter followers that ISIS wouldn't be communicating through the app anymore.

"This week we blocked 78 ISIS-related channels across 12 languages. More info on our official channel," read the tweet, date Nov. 18.

This week we blocked 78 ISIS-related channels across 12 languages. More info on our official channel: https://t.co/69Yhn2MCrK

— Telegram Messenger (@telegram) November 18, 2015

The communication firm released a statement saying they were "disturbed to learn that Telegram's public channels were being used by ISIS to spread their propaganda." This, despite the fact that Telegram was well-known tool of ISIS.

According to the Telegraph, Telegram founders Nikolai and Pavel Durov pride themselves on the app's secrecy and freedom of speech.

Telegram launched their "Channel" feature about two months ago as a means of broadcasting messages akin to Twitter. ISIS supporters jumped on the platform and began spreading propaganda to thousands. The app's administrators knew of ISIS and ISIL's presence but chose inaction.

The app, after all, was the Durov brothers' way of defying government influence. They created Telegram to speak with friends and family without interference from the Kremlin, Russia's omnipresent governing body. Before that, the Durovs' created VKontakte, a social networking site comparable to Facebook, only more popular among Russians.

Once ISIS praised the Nov. 13 Paris attacks, Telegram had no choice but to backtrack, to an extent.

"If criticising the government is illegal in a country, Telegram won't be part of such politically-motivated censorship. This goes against our founders' principles," the firm said in a statement. "While we do block terrorist (eg ISIS-related) bots and channels, we will not block anybody who peacefully expresses alternative opinions."

Some are calling for Telegram, and similar encrypted chat programs, to be shut down. An Oct. 29 report from the Middle East Media Research Institute vehemently opposed Telegram's "Channel" service because of how feasible it was for extremists.

"Jihadis' use of Telegram and other secure messaging apps has gained momentum in the last year, for purposes such as communications, propaganda, and recruitment," researchers wrote. "The new service offered by Telegram constitutes a step up from the standard one-on-one messaging function, and there seems to be no way to censor it."

As one Islamic State supporter said, "the war on Telegram has started." The message was shared by ISIS propaganda expert Charlie Winter, who tweet a warning, written in Arabic, meant to threaten Telegram.