So, what would be an effective way of making censorship impossible?
I imagine a system where you publish news using your device (a mobile phone), and encrypted in a way so that only a small group of other devices, which you have explicitly trusted in an earlier step, can decrypt it, allowing only them to trace that the news came from you.
Then those trusted devices will decrypt and re-encrypt the news in such that they can forward it with only their trusted devices. When a device receives news from another, then it won't know whether the sender published that news, or is merely forwarding it.
Because all communication between devices is encrypted, a device can not be confirmed to be using this system, except by a device who he trusts.
When a device is compromised, he will only be able to see if another device is part of the system, if that device has trusted him. Also the compromised device will be able to read news shared to him, but he won't be able to see what device that news originates from.
To make sure that readers can filter news based on what publishers they like, there is the concept of a publisher.
Apart from news, devices can also share publishers. An publisher is a name plus public key. The creator of the publisher has the private key with which he can encrypt news (even before it encrypted for sharing), allowing readers of that news, who have the publisher's public key, to verify that the news came from that publisher. If a publisher is shared with a device while the device already knows a publisher with the same public key, then the device must chose which publisher to keep and which to delete.