I am quite sure surveillance isn't any easier (or any harder) with IPv6. Privacy extensions https://tools.ietf.org/html/rfc4941 https://tools.ietf.org/html/rfc4

I am quite sure surveillance isn't any easier (or any harder) with IPv6. Privacy extensions https://tools.ietf.org/html/rfc4941 https://tools.ietf.org/html/rfc4941 randomize the source IP so there are in theory 2^64 possible combinations for each /64 prefix. Also, if you don't even communicate with the outside world, the situation is the same with or without NAT as you have to traverse some controlled point otherwise. I don't think the typical home router in China does monitor the traffic, there would be too much data and a lot of noise. It is much easier to sit on the pipe at a central point somewhere and detect patterns there. There are sufficient surveillance mechanisms today with IPv4 that are at least similar to what we have available with IPv6. In China and in most other countries in the world (in some maybe only after ordered by the court) will hand out records to agencies for further analysis. They will almost certainly be able to come to robust conclusions with both IPv4 and IPv6 if they really want to, since they can obtain most of the relevant data quite easily. Big internet companies also have their sources (e.g. login, other means of tracking) so it is hard to fully escape that as well. So unless you are doing a lot to break this kind surveillance, you will have a hard time to stay truly anonymous for extended periods of time.