On May 1 Iran announced that, following Russia, it too would be blocking access to Telegram for its citizens.
Telegram, a popular messaging app which offers end to end encryption, was blocked by Russian authorities in mid-April after the company refused to provide the government with encryption keys. While Telegram claimed that this was not technically feasible, Russia stated that it required access in order to investigate a train bombing in St Petersburg last year that killed 15 people.
Iran is similarly pointing at the use of Telegram by terrorists linked with ISIS that carried out an attack last year in Tehran. But the government of Iran has been wary of how Telegram has been used in the organisation of political dissent within the authoritarian country for some time.
Prior to the new man, Iran required that its citizens register any Telegram channel with 5,000 followers or more. Around 2,000 channels were subsequently registered as a result of this law, but there was little question that further restrictions would emerge when Ayatollah Alia Khamenei, the Supreme Leader, closed his own Telegram account, and when employees of the government were forbidden to use the app.
There are questions over how serious Iran is about the block. Unlike in Russia, where IP addresses were quickly blocked to enforce the ban, currently the service still seems to be functioning in Iran. Even if the government does choose to block access, this can easily be circumnavigated by the use of cloud networks, such as those of Amazon and Google. If the government wishes to make the block effective, these services would also need to be blocked, as they have been in Russia, causing significant disruption.
Even if Iran pursues this course of action, the service would still be accessible via VPN (Virtual Private Network), to which the Iranian government does not currently have the technological capability to block access. It seems unlikely that the government will be able to enforce their mandate.
This is good news for the 40 million Iranian users of the service. This represents half the population of Iran, and 20% of Telegram’s entire market.
But Telegram may not be as secure as its users think or hope. While it has a reputation for security thanks to its end to end encryption of messages, not all of the messages communicated via the service are encrypted in this manner by default. This level of security, which means that messages can only be decrypted using the intended recipient’s phone or device, is only provided in the optional Security Chat mode.
The use of a bespoke, non-standard MTProto encryption protocol by Telegram is also criticised by researchers, as well as Telegram’s use of closed source binary blobs in its open source code.