Making Data Unvanish

sertsa writes "Earlier this year a group of researchers at the University of Washington came up with a scheme to use peer-to-peer networks to store and, ultimately, to forget the keys for encrypted messages, causing them to 'Vanish.' Now a group from researchers from UT Austin, Princeton, and the University of Michigan has come up with a way to break this approach, by making a single computer appear to be many nodes on the p2p network. 'In our experiments with Unvanish, we have shown that it is possible to make Vanish messages reappear long after they should have disappeared nearly 100 percent of the time...'"

Comments

Sparring

[spydabyte]

They certainly are sparring, see the University of Washington response:

Update, 9/20/2009: Other researchers have recently discovered a vulnerability in our original Vanish research prototype. Their work shows that the Vuze DHT on which we built the original prototype did not provide sufficient security properties, and that there are therefore attacks that can capture Vanish keys. We released a revised prototype on September 20, 2009. This revised prototype, which distributes keys across both the Vuze DHT and OpenDHT, invalidates this attack. In addition, we are working to further strengthen Vanish from two angles: (1) by hardening the underlying DHT for Vanish-like purposes and (2) by modifying applications to make more intelligent use of DHTs. Please see our new technical report for additional information about the currently known attacks and our defenses. Due to the complexity of the systems we are relying upon, we would like to strengthen our advice that users should be cautious if they want to use Vanish. At this point, Vanish should only be used for experimental purposes. We do encourage researchers, however, to analyze it and improve upon it.

Re:Sparring

[sopssa]

We released a revised prototype on September 20, 2009. This revised prototype, which distributes keys across both the Vuze DHT and OpenDHT, invalidates this attack.

But does this *really* invalidate this type of attack? It seems it just adds another p2p protocol on it, and it would still be as vulnerable as before. Only difference seems to be that the current tool just doesn't work at the moment. Approach would still be the same.

Re:Sparring

[vlm]

But does this *really* invalidate this type of attack? It seems it just adds another p2p protocol on it, and it would still be as vulnerable as before. Only difference seems to be that the current tool just doesn't work at the moment. Approach would still be the same.

I think the UW folks are reading slashdot and editing their page as we speak. The page now includes the quote:

This revised prototype, which distributes keys across both the Vuze DHT and OpenDHT, invalidates this attack. This is because OpenDHT has a closed-access model as opposed to an open-access model like Vuze, which is what drives the current attack. In addition, we are working to further strengthen Vanish from two angles:

So, Vanish people, I know you're listening, please respond to my being unclear how a closed-access model prevents the attack as opposed to just makes it a wee bit harder for small weak opponents, not so much impact to bigger ones.

Freenet

[westlake]

Now a group...has come up with a way to break this approach, by making a single computer

I have often wondered if Freenet would be vulnerable to such an attack.

Freenet needs the super-user with generous amounts of storage and bandwidth.

Which its well-funded adversaries can provide in spades. Thousands of nodes. Tens of thousands of nodes. Hundreds...

It seems that sooner or later they would be capturing enough of the traffic to begin putting the pieces together - or sending them into the void.