IPv6 may make fingerprinting harder since you might lose a single static identifier for users. Of course, you could gain a unique identifier per device on a subnet without security measures there.

However, it doesn't affect cookies which are bound to origin names rather than addresses.

That's a good point. Static IPv6 addresses or even a (small) pool of them could make for a reliable ID.

Wonder how people should work around that?

https://tools.ietf.org/html/rfc7217 is one way.

Not really. ipv6 has nothing to do with any of this.

Yes it does. Users now have a unique IP address that is now static. Yes you can rotate your exact IP inside your block but you still keep the same subnet.

That is the promise they sold it on.

But, point me to a single ISP that gives a cable subscriber more than one IPv6 address. or a /48 as initially everyone was hopping.

ISP profit from NAT. They will never get rid of it. Even if you get a /54 /64 the ad networks will just learn to assign /54 as they do today.

But, another point, ipv4 today is barred from being used to form your advertising profile under current legislation.

Comcast gives you a /60 block that you can assign multiple /64's out of.

My computer rotates out IPv6 addresses every 30 minutes using SLAAC with privacy addresses.

While you can identify the /64, there is no guarantee that it is a single user, just like in IPv4 because of NAT there is no guarantee it is a single user. It'll identity a household, but that's it.

> just like in IPv4

is the key concept I am talking about here and everyone keep saying it is not.

Just like ipv4 is what matter and why ISP will never kill NAT. They profit from it, somehow. and it is not just saving money on ipv4 address space.

My ISP (Andrews and Arnold) does exactly this.

https://support.aa.net.uk/IPv6

"Customers are allocated a /48 block of addresses - this is usually per customer, and so a customer with multiple circuits or sites will have a /64 allocated from the larger /48 block"

Spectrum assigns a /128 to your router via DHCPv6, but you also get a delegated prefix. That prefix seems to be a /64 by default, but you can request and receive a /56.