Many people who focus on information security, including myself, have
long considered
Telegram suspicious and untrustworthy.
Now, based on findings
published by the investigative journalism outlet ISt
The two decisions Telegram made (choice of infrastructure provider who happens to cooperate with the Russian FSB, and attaching a cleartext device identifier to encrypted messages) taken together reinforce surveillance capability of the FSB considerably more strongly than either of these decisions would have on its own.