Investigation by investigative journalism outlet IStories (EN version by OCCRP) shows that Telegram uses a single, FSB-linked company as their infrastructure provider globally.
Telegram’s MTProto protocol also requires a cleartext identifier to be prepended to all client-server messages.
Combined, these two choices by Telegram make it into a surveillance tool.
I am quoted in the IStories story. I also did packet captures, and I dive into the nitty-gritty technical details on my blog.
Packet captures and MTProto deobfuscation library I wrote linked therein so that others can retrace my steps and check my work.
This is the part that resonated with me the most as the casual user. The interface is, so confusing that the differences between various forms of chats seems deliberately unclear. And all that’s “useful” is opt-in. And Groups - most used in corporate or project setting, can’t be encrypted at all? That’s… peculiar.
Again, thanks for the eye-opener.