Seems like UDP is completely exempt, which would allow UDP-based VPNs, like Wireguard through.
SSH is also exempt...
SSH is also exempt...
Could you explain this further, this seems counter to my understanding of encrypted traffic!
Active web browsing requires downloading a crapton of files with wildly different sizes and sporadic timings between them. Add normal user interaction, API requests, ad cycles, long video streams that won't max out all bandwidth, all happening at once across multiple tabs. The client also sends much more data with each TLS handshake and all those HTTP headers.
This could probably be masked by deliberately filling idle periods with garbage data just to appear as a stable data stream both ways.
Not much good for images or video, but you could easily read https://text.npr.org/
[0] https://unix.stackexchange.com/questions/12755/how-to-forwar...
Your mistake is assuming that China has rule of law. If you're in China and you upset Xi enough, you get jailed/disappeared even if you technically didn't break any laws on the books.
It doesn't seem that there are any (long term) solution to bypass the rules ...
So for now, circumvention can live on, but this explains to everyone using fully encrypted protocols exactly why their connections would have been degraded over the past couple years. In the long term, steganography will probably work well as long as users are able to endure much higher costs for traffic (low ratio of true data to apparent data) and as long as the steganographic systems are effective at hiding any statistical fingerprints (very difficult). Protocol mimicry is another strategy, but a paper cited in this work details why successful protocol mimicry is very difficult.[0]
Attempts to disguise circumvention traffic as typical traffic is very difficult, because a lot of fingerprinting information can be gleaned from handshakes and headers. The draw of fully encrypted traffic is that it provides very little variation which can be used to fingerprint and classify different types of usages. However, it's also easy to detect and block en masse -- that much is obvious, but this paper does a great job of showing how China does it and inferences can be made from that to provide a view into China's priorities (how much cost they're willing to incur, rates of false positives they feel is acceptable). Overall, China's blocking current appears to be fairly conservative here, with relatively low rates of false positives.
In wider context, China is constantly updating their detection schemes, they're quite competent at it, and anything which doesn't match typical traffic is at risk.