Individual messages can be fully encrypted. But the user has to turn on that function. It's not automatic, as it is on Signal and WhatsApp. In the United States, Telegram's lower public profile has helped it mostly avoid high level scrutiny from Congress, but it has not gone unnoticed. Lastly, the web previews of t.me links have been given a new look, adding chat backgrounds and design elements from the fully-features Telegram Web client. Such instructions could actually endanger people — citizens receive air strike warnings via smartphone alerts. 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.
from tw