"The argument from Telegram is, 'You should trust us because we tell you that we're trustworthy,'" Maréchal said. "It's really in the eye of the beholder whether that's something you want to buy into." The gold standard of encryption, known as end-to-end encryption, where only the sender and person who receives the message are able to see it, is available on Telegram only when the Secret Chat function is enabled. Voice and video calls are also completely encrypted. The message was not authentic, with the real Zelenskiy soon denying the claim on his official Telegram channel, but the incident highlighted a major problem: disinformation quickly spreads unchecked on the encrypted app. Groups are also not fully encrypted, end-to-end. This includes private groups. Private groups cannot be seen by other Telegram users, but Telegram itself can see the groups and all of the communications that you have in them. All of the same risks and warnings about channels can be applied to groups. Also in the latest update is the ability for users to create a unique @username from the Settings page, providing others with an easy way to contact them via Search or their t.me/username link without sharing their phone number.
from ar