Who cares about the protocol?
BitTorrent most certainly has taken a huge hit just by being associated with piracy, but regardless that's not very interesting. There are tons of ISPs etc. that filter BitTorrent, but that's mostly because it puts a strain on the network. Aside from that few has been attacking the protocol itself.
If emailing was considered illegal and google, microsoft et al would shut down their servers, you would still be able to email people.
Though far from anyone, and you might need to remember that odd IP because the DNS queries for popular people might be blocked depending on where you live.
If that was the case, would email be dead? Yes.
Would email as a protocol be dead? No. But it would be dead in the eyes of the public.
And that kind of defeats the "censorship becomes a non issue". By that logic censorship in china is also a non-issue. Because you can circumvent the great firewall with VPNs. Never mind that you have to be tech savvy and take personal risks, but despite that it isn't a non-issue to the public. And that's enough.
DNS is a problem for censorship resistance. The solution is not to identify people by their IP address, but to identify them by a unique token which cannot be forged by anyone else (a public key).
In place of DNS, you have distributed gossip protocols which map public keys to IP addresses, and where the messages in that protocol are digitally signed using the private keys for that public key, such that you couldn't have the equivalent of "DNS spoofing".
You can also use the same public keys to perform an authenticated DH key exchange and then have all of your communications encrypted and MITM resistant.
A public key would be like a phone number. You give it out to the people you want to have it directly.
We're effectively in an arms race right now where one side is determined to tightly control internet traffic like the Chinese firewalls, and the other side is developing distributed protocols which resist these censorship efforts. The latter has had a significant boost with the invention of Bitcoin, which can now be used without an internet connection, over SMS, satellite, radio and whatever else. This isn't going to be a trivial thing to shut down.
Gossip is P2P. The protocols can be hidden as if they were SSL or some other widely used protocols, but without the PKI and the centralization problems that has. Evading the censors will probably be a continuous effort. The great firewall has not succeeded in preventing the use of proxying services and VPNs, despite the efforts.
If internet censorship becomes too widespread, people will use other communication mechanism to conduct trade. As I mentioned, Bitcoin is broadcast over satellite and radio in some locations. You can send a transaction as an SMS message. A bitcoin transaction is ~250 bytes and can be encoded as a sequence of 16 emojis. I can print a bitcoin transaction on paper and the recipient can scan it.
Sure, but "evading the censors will probably be a continuous effort" and "censorship becomes a non-issue" are not compatible in the real world.
Even despite that the great firewall has not succeeded in preventing the use of proxying services it still is a massive success. And despite all the ways you can circumvent it censorship very much continues to be an issue, I'd argue more so for every day.
The instant such SMS message transactions become popular a quick filter will kill that if the need for it arises. And SMS is hardly the technique for privacy minded communication (neither is bitcoin).
What remains is perhaps ham radio. Still easy to triangulate, jam and is not accessible to anyone but the most extreme. Making triangulation even more desirable and paints an even greater target on your back.
Printed copies are hardly something to look forward too, it also excludes pretty much everyone. Cash would be quite superior unless you are transferring huge amounts (which most won't).
Right. So the next step is covert channels. And given how much high-definition video is bouncing around, there's lots of potential covert bandwidth. Even at the ~0.1% level.
No, not likely Netflix. But there's lots of small-scale YouTube stuff. And video messaging.
Edit: So let's say that you enjoy porn. But all the ISPs are blocking it. And let's say that there was a system where you could get what you wanted, in exchange for routing other stuff. Like some mix of Tor, I2P and Freenet, except as covert content in innocuous HD video.
If emailing was considered illegal and google, microsoft et al would shut down their servers, you would still be able to email people.
Though far from anyone, and you might need to remember that odd IP because the DNS queries for popular people might be blocked depending on where you live.
If that was the case, would email be dead? Yes.
Would email as a protocol be dead? No. But it would be dead in the eyes of the public.
And that kind of defeats the "censorship becomes a non issue". By that logic censorship in china is also a non-issue. Because you can circumvent the great firewall with VPNs. Never mind that you have to be tech savvy and take personal risks, but despite that it isn't a non-issue to the public. And that's enough.