Mullvad has partnered with Obscura VPN

[jonah (Jonah Aragon)]

@ignoramous

The Obscura app registers your “WireGuard keys” (hopefully, rotated often

I also poked them for some details on Discord about this, this morning.

@jonah

How often are WG keys rotated? It seems like your client’s public WG key could be used as a static device identifier by Mullvad, couldn’t it?

@Obscura VPN

We currently rotate on every connect, but are internally testing local key caching (so that API servers aren’t overwhelmed) with key rotation at regular intervals.

@jonah

Do you think this is a concern for some people? It may not be obvious to users that if they go to Site A and Site B on the same connection, that activity could be correlated by your exit provider.

@Obscura VPN

I see what you mean: inter-connection correlation on the exit hop can still happen with Obscura.

Our main privacy goal, at least for this initial launch, is to sever the correlation between identity (IP address, payment info), and traffic/connection.

With this improvement, inter-connection correlation becomes a bit less worrisome, but admittedly is not solved.

One big mitigating factor is that we’ve deliberately chosen Mullvad as our exit hop partner, and we believe them to be very trustworthy

Thinking about it on a protocol level, I think we’ll need something other than WireGuard for this to work.

@jonah

Yes, I certainly agree this is a huge improvement over just Mullvad or another provider. It is not a gotcha question, I was just curious about your opinion on the issue. I know that Apple spent significant effort on the authentication aspect of their Private Relay protocol to alleviate this concern for example, so when we were reading about your (seemingly much simpler) solution with WireGuard it gave me and some of our other community members on the Privacy Guides forum pause.

I do worry a lot about people being over-confident in their privacy & security tools, generally speaking. I wonder if there is an opportunity to educate people about this risk. Key rotation would probably help a lot here I’m guessing, and giving people the option to manually rotate (as well as informing them when that might be necessary ahead of time) would as well. Of course it sounds like they already have that option, but may not know when it’s necessary in certain scenarios.

There’s always the risk of Mullvad correlating traffic by inspecting it and inferring some relationship no matter what you do probably, but that is a whole different issue than right now where it would actually be relatively trivial.

I think correlation between before and after you rotate WireGuard keys really shouldn’t be possible right? Or am I overlooking some other potential identifier in your/WireGuard’s protocol?

It’s like you say, Mullvad is very trustworthy, but when the goal is to minimize trust then I think you have to be clear when trust is still required. It is clearly a very different situation if Mullvad can say “this traffic came from this specific Obscura VPN user, but we don’t know their identity” as opposed to “this traffic came from an Obscura VPN user, and we don’t know their identity.”

Still waiting to see if they have any thoughts on my last messages, but it’s good to confirm this specific limitation.

Edit:

@Obscura VPN

What a wonderfully thoughtful comment!

Yeah this kind of correlation is exactly why we’re going to ship key caching/persistence with regular key rotation, so at the very least the correlation is broken every rotation.

It’s an interesting idea to allow users to maually rotate keys, I hadn’t really thought of that before! I think that user education and crafting UI that’s powerful without being overwhelming to a non-expert audience is inevitably a large part of the work that’s ahead for Obscura and other privacy-conscious companies, but it’s part of the good fight!

It also sounds like I really need to check out the Privacy Guides forums more often!