What is Telegram and why has its founder Pavel Durov been arrested?

The arrest of Pavel Durov, the Russian-born founder of Telegram, in Paris on Saturday has thrown the spotlight on the messaging app. Prosecutors said on Monday he was being held in custody as part of a cybercrime investigation.

What is Telegram?

At its core, Telegram is a messaging app, competing with services including WhatsApp, Signal and iMessage. For many of its users, it’s nothing more than that: a good place to chat with friends.

But the app also offers more social networking features than most of its peers. Group chats are in effect unlimited in size, as are Telegram’s broadcast “channels”, which let users “follow” individual accounts.

Those channels also let followers leave comments under posts, and have back and forth conversations with each other, in a manner far more reminiscent of a Facebook group or even an old-school internet forum than a simple instant messaging service.

Is it encrypted?

That is a surprisingly controversial question. “Everything on Telegram, including chats, groups, media, etc is encrypted using a combination of 256-bit symmetric AES encryption, 2048-bit RSA encryption, and Diffie-Hellman secure key,” the company says, and that’s true. But it’s a different sort of encryption to that which has become standard in messaging apps, known as end-to-end (e2e) encryption.

For Telegram users, unless they go through a laborious process of setting up a “secret chat” (which isn’t an option for group chats or broadcast channels), their messages aren’t protected from being read by Telegram itself – and so Telegram doesn’t have the same excuse for not aiding law enforcement that its competitors can turn to.

Who’s got Telegram’s back?

Despite that different approach to security, Telegram has long appealed to communities who haven’t found a home on more mainstream platforms; cryptocurrency advocates, anti-vax activists and QAnon believers have all migrated to the platform after crackdowns on social networks such as Facebook.

Durov, once known as the “Russian Mark Zuckerberg”, has spoken about his belief in the importance of free speech, and others with similar absolutist views, including Elon Musk, have come to his defence.

Surprisingly, Russia has also expressed its concern about the arrest. The state in effect seized control of his first company, Facebook clone VKontakte, and Telegram was founded by Durov in exile.

He is now believed to hold three other citizenships beside his Russian passport, but that hasn’t stopped the Russian foreign ministry from attacking France for its detention of the chief executive.

Why did the French arrest Durov?

The French allegations are, broadly, that Telegram failed to fight the use of the service for crime – including the spread of child sexual abuse material.

The investigation concerns crimes related to illicit transactions, child sexual abuse, fraud and the refusal to communicate information to authorities. The arrest warrant was issued by OFMIN, a French child protection agency, the group’s secretary general said in a post on LinkedIn.

It is extremely rare to hold the providers of web services liable for the actions of their users, and rarer still to append personal liability. What remains unclear is whether the alleged failures of Telegram are extraordinary, or if the escalation is instead on the part of the French authorities.

In a statement on Sunday, Telegram said Durov “had nothing to hide” and that “it is absurd to claim that a platform or its owner are responsible for abuse of that platform”.

What does this mean for other messaging services?

Some have already spoken out in fear of a “chilling effect”, with executives feeling like they need to over-moderate and over-censor their services lest their own safety is at risk whenever they jet to Cannes for a holiday.

The arrest is also likely to hasten the move to adopt universal end-to-end encryption, with leaders unable to be held liable for content they cannot see.

The specifics of Durov’s arrest remain unclear, particularly whether his behaviour was in line with industry standards.

In 2015, for instance, Telegram’s founder famously dismissed accusations his platform was a safe haven for Islamic State, arguing only that “privacy is more important than our fear of bad things happening, like terrorism”.