[chaseha]

Would homomorphic encryption or any other privacy enhancing technologies allow for a middle ground here?

Would allow you to scan the encrypted messages for incriminating or illegal content when there is reason to believe a specific account is doing something illegal (could require court approval, then a further process for full decrypted messages as part of court proceedings)

[quazar]

In one-key scheme you, the encryptor, would also have to encrypt the naughty word list, allowing you to cheat, so it will not be allowed.

[chaseha]

Ahh interesting. So you could not have one key encrypting the messages than a separate org-wide key encrypting the naughty word list. That makes sense. Thanks.

[quazar]

I think there are some multi-key schemes but they are much more expensive and very rarely used, I don't know much about them