Oh, come on! If Telegram can decrypt chats for a user, they can decrypt it if they really want. Any other kind of encryption is irrelevant - from third party attackers, tls works good enough.

Yeh "endpoint security" is hard. You need some trusted specialized hardware or network.

https://en.wikipedia.org/wiki/End-to-end_encryption#Endpoint...

Dealing with the endpoint security is a really tough problem but I have a pet-project that pushes the price per endpoint just below $500 https://github.com/maqp/tfc