Blog post by crypto professor Matthew Green, discussing what Telegram does (I wasn’t familiar with it) and criticizing its cryptography. He says Telegram by default is not end-to-end encrypted. It does have an end-to-end “secret chat” feature, but it’s a nuisance to activate and only works for two-person chats (not groups) where both people are online when the chat starts.
It still isn’t clear to me why Telegram’s founder was arrested. Green expresses some concern over that but doesn’t give any details that weren’t in the headlines.
This is not true, it is available in the open-source Telegram clients.
What you probably mean is that it is using an unusual and not well studied encryption algorithm. This means you need to be a real cryptography expert to spot flaws in it.
Telegram justifies this with a bit of FUD about well known encryption algorithm being NSA sponsored etc, but when cryptography experts did look at Telegram’s homegrown algorithm they were less than impressed.
As I recall, Telegram put up bounties for people actually demonstrating exploits in its encryption. Have any of these cryptography experts actually shown exploits?
Removed by mod
But can you provide an example of an actual flaw being demonstrated by anybody with or without a bounty?
Removed by mod
And I’m saying that despite people constantly throwing shade on the protocol, nobody has actually showed any flaws in it over many years. The whole dogma that non-standard protocols and algorithms should be shunned out of principle is just that. Meanwhile, plenty of exploits have been found in standard protocols. Not only that there are known cases where US security agencies introduced exploits into popular protocols. https://www.theverge.com/2013/12/20/5231006/nsa-paid-10-million-for-a-back-door-into-rsa-encryption-according-to