Allow write-only access to a room

[IngoHohmann]

I see many use-cases, where only sending into a room is needed:

• Monitoring systems
• IoT devices which ony send messages
• Web-Forms sending into Matrix
• ...

In the spirit of only giving the minimal set of rights, these accounts should only have write-acess, so if someone gets a hold of the used access_token, he will not be able to read messages.

This point is especially important for usage with web-forms.

[turt2live]

Set the power level to send messages to be 2.
Set the power level for new users to be 0 (default).
Set the power level of the accounts you want to be able to speak to 2 or higher.

[IngoHohmann]

This means normal users would be read-only,
special users could read and write.

I want users who can send, to not be able to read messages in the room.

[reivilibre]

This would need something to be specced up. But a workaround might be to use asymmetric crypto so that messages can only be decrypted by a certain client with the keys.