Encryption without super access

Question

I want to have a form for users on a website where the messages are encrypted, so that not even the hosting company or the super administrator can read them. Only people in the same team can read the messages, but the messages are still hosted on the server. How to do this?

Answer 1

You could do the encryption with JavaScript on the client side. See this question for a few suggestions.

However, you're still susceptible to interference from malicious administrators editing the JavaScript. I can't really see a way around that; you can't trust code running on an untrusted server.