Secure messaging app Telegram gains end-to-end encrypted voice calls

In an age of constant surveillance and eroding privacy, there is increasing interest in secure messaging platforms such as WhatsApp and Telegram. While Telegram has gained quite a following, there is one feature that users have been begging for: voice calls.

Now users' prayers have been answered. The latest update to Telegram finally heralds the arrival of secure voice calling, and it features an interesting key exchange mechanism: users need just compare four emoji. If the emoji match, the connection is secure!

Audio quality is kept as high as possible not only through the use of the best codecs, but also by using a peer-to-peer connection. If this is not possible, Telegram will simply use the closest server instead. Developers says that call quality is "superior to any of our competitors", and this is thanks to artificial intelligence.

Each time you make a Voice Call on Telegram, a neural network learns from your and your device's feedback (naturally, it doesn't have access to the contents of the conversation, it has only technical information such as network speed, ping times, packet loss percentage, etc.). The machine optimizes dozens of parameters based on this input, improving the quality of future calls on the given device and network.

These parameters can also be adjusted during a conversation if there's a change in your connection. Telegram will adapt and provide excellent sound quality on stable WiFi -- or use less data when you walk into a refrigerator with bad reception.

Telegram acknowledges that voice calls have been a much-requested feature, and explains how security has been updated:

Telegram Calls are built upon the time-tested end-to-end encryption of Telegram's Secret Chats. The key verification UI we came up with in 2013 to protect against man-in-the-middle attacks served well for Telegram (and for other apps that adopted it), but for Calls we needed something easier.

That's why we've improved the key exchange mechanism. To make sure your call is 100% secure, you and your recipient just need to compare four emoji over the phone. No lengthy codes or complicated pictures!

As detailed in the changelog, encrypted calls are rolling out worldwide over the next few days:

• Telegram Calls are here: secure, crystal-clear, constantly improved by artificial intelligence. We are rolling them out in Europe today, the rest of the world will get calls within a few days.
• Choose between 5 grades of video compression and preview the quality of your video before you send it.

As you can see, the update also brings improvements to video quality, but it's the promise of secure calls that's the real headline-grabber here.