As I said earlier, it is only somewhat similar to TLS-in-TLS blocking. I do not have exact articles right now, and it is not easy to google them, since almost all of them are in Chinese.

But here is for example, a proof of concept of a tool, that detects TLS-in-TLS: https://github.com/XTLS/Trojan-killer

It is incomplete and I do not know if it uses the same methods as Chinese censors, but it still proves the possibility.

If you still require more concrete proff, then, I will try to find an article in my free time and if I do, I would reply to your comment again after that (it is not going to be in the nearest future.

Please explain how are you imagining that

I do not have right now links to articles about that exactly, but here is an old article about somewhat similar tactics that China uses to block encrypted proxy protocols like shadowsocks, for example: https://gfw.report/publications/usenixsecurity23/en/

I’m talking about encapsulating traffic in an encrypted tunnel.

As I I have previously mentioned, if you are encapsulating all traffic in an encrypted tunnel, then most of the data would have two layers of encryption. This can be detected, and, in fact is being detected in China and, experimentally, in Russia.

The beautiful website I’ve imagined for a situation where some DPI robot will, say, visit it to check that there really is a website there.

That is a good protection against active probing, but active proving is not the only detection method, available for censors.

You also seem to be mixing up such entities as VPNs, proxies and encapsulation.

How did you come to this conclusion?

BTW, I’m using VPNs in Russia from time to time. Something doesn’t work, something does.

What are you trying to say here? What does work? What does not?

I’m describing a specific kind of encapsulation.

What I understood from you is that you are talking about encapsulating TLS-encripted traffic in https, TLS-encripting it again. If I understood you wrong, please correct me. There are countless software solutions for that, but they are not panacea, because double layer of encryption can be detected and your beautiful website does not need encryption-on-top-of-encryption. It is obvious that you are reaching something else.

It is going to show the censor that you are trying to reach different banned websites (and, probably, google, facebook, etc), all hosted on your server. Your beautiful website is all fine, but in clienthello there is still google.

It is not necessary fingerprinting of clients, you can fingerprint the server as well. GnuTLS for this particular purpose is used only by Openconnect and that is just an example. This tactic is very effective in China and Russia and collateral damage is insignificant.

And various western anti-censorship organizations wrote articles, that such methods are not possible in Russia as well, but here we are. China’s yesterday is Russia’s today, American tomorrow and European next week. Here it all started in the exact same manner, by requiring ISPs to block pirate websites. And between this and blocking whatever you want for the sake of National Security (for example, against Russian hackers) is not such a long road as you think it is.

At first, please, be a little bit more patient and no, I am not a LLM.

All https traffic is https-encapsulated by definition. And you can look inside https just fine. The problem is that most of data is TLS-encripted. However, there is so-called “clienthello” that is not encripted and can be used to identity the resource you are trying to reach.

And if you are going to https-encapsulate it again (like some VPN and proxy protocols do) data will have TLS-encription on top of TLS-encription, which can be identified as well.

And about libraries: VPN protocol Openconnect, for example uses library gnutls (which almost no one else uses) instead of more common openssl. So in China it is blocked using dpi by this “marker”.

By the same logic they should not be able to force ISPs to ban sites, but here we are. If they can enforce bans with ISPs, why can’t they do the same with VPN providers?

Https does not actually make difference here. You can still detect VPN usage by unencrypted clienthello, encryption-inside-encryption, active probing, obscure libraries that vpn protocol depends on, etc.

VPNs are not categorically banned in Russia either. Just 95% of them. Categorical ban is not actually required here. Government can just create licensing procedure and license only those VPNs, which follow “rules”. I do not see how this is different from ISP bans.

As a guy from Russia, I must admit that vpns are not a big problem for censors. They can be easily blocked, including self-hosted ones by protocol detection. And DNS would not do much with IP and clienthello-based blocks. And most users are not enough tech-savvy to constantly switch to new protocols as old ones get blocked.