In the case of Telegram, MTProto’s implementation leaves a lot to be desired[1][2].
Additionally, home rolled crypto does not usually get the kind of security review from the cryptography community which makes it very likely that bugs of all kinds exist.
Additionally, home rolled crypto does not usually get the kind of security review from the cryptography community which makes it very likely that bugs of all kinds exist.
[1] https://words.filippo.io/dispatches/telegram-ecdh/ [2] http://unhandledexpression.com/2013/12/17/telegram-stand-bac...