If you think about it, what does it mean that content is illegal? How can you forbid a set of ones and zeroes?
It's a fake idea we've invented, and new technology has a way of forcing us to realize that.
That said, practically, the world will adapt however it adapts. If we can survive the advent of unbreakable encryption, a little trolling won't matter much.
This is like asking, "How can you forbid a set of iron atoms?" in reference to guns.
Guns can cause harm. Does information?
If someone photographs your private life and makes it public, that could be called information. But it's not quite the same: That's an action that goes against your will, and it seems quite ethical to let you enforce it.
Yet even still, how do you propose to do that? What happens when a service literally cannot delete the information? And when that service becomes crucial infrastructure, what then?
These are questions that technology is going to force us to address. Pretending that it's naive won't change that. Decentralization is coming.
To your edit, you're just punting the question. What do you do when the information cannot be removed, and the service is critical infrastructure? What happens when the content is in a decentralized internet that everyone uses, and that everyone receives automatically?
You can punish the uploader, sure. But do you ban the service? You'll take part of your population with it. Most countries seem to agree that banning Bitcoin is a bad idea, for example.
So what do you propose?
I'd do what we do with every advancement that challenges are existing paradigms: study it, debate it, and seek out creative and equitable ways to deter the negative externalities. That may involve banning, restricting or regulating services.
> What do you do when the information cannot be removed, and the service is critical infrastructure? What happens when the content is in a decentralized internet that everyone uses, and that everyone receives automatically?
Even in this scenario, there is still going to be a common denominator that can be regulated to control illegal content (ISPs for example).
Imagine that Bitcoin's genesis block contained an encrypted image. Satoshi today releases the key, and it turns out to be the worst image imaginable. BTC doesn't drop; the price keeps going up over time. What do you do?
If you have an answer, it would be an important one.
I mean this quite seriously: Should feelings alone be enshrined and protected? It's a strange question with no clear answers.
What happens when everyone automatically receives all content, and the content cannot be deleted? Now assume the service is something everyone uses. Imagine it's a decentralized internet, and banning it will cause your country to fall behind. What do you do then?
This isn't quite a baseless hypothetical. It's one logical outcome of decentralization. And sooner or later, we're going to need to answer these hard questions.
But that's also an answer to your question. It's easy to imagine if Bitcoin were. So let's say it was. What do you do now that Bitcoin is $6k?
(It's easy to argue that Bitcoin may not have attained $6k if it embedded an image renderer. But I think a future service will attain the same importance.)
This doesn't stop just because the technology is unable to delete anything.
You can try to make Ethereum illegal if you want, but it'd be a tactical mistake. Ditto for unbreakable encryption.
In fact, explain why it makes no sense to make unbreakable encryption illegal. Show your work. I suspect the same argument you'd use for that will apply to this.
Required reading: http://ansuz.sooke.bc.ca/entry/23
The courts seem to think they can make some numbers illegal: https://en.m.wikipedia.org/wiki/Illegal_number