Telegram lost it credibility in how they handled criticism when they firs launched. They were arrogant ("look at all the programming world champions we have. If

Telegram lost it credibility in how they handled criticism when they firs launched. They were arrogant ("look at all the programming world champions we have. If you don't have an exploit STFU" type of talking). The criticism people came with was valid. After half a year a russian guy found that the server could backdoor and later decrypt any newly started secret chat. That wasn't very confidence-inspiring back then. Looking at their security documentation now is _still_ painful. What better lesson to not roll your own crypto is there than having someone show how badly you borked it? They didn't learn anything.