What about keysigning among tor operators? I trust top_op1, and he trusts top_op2, 3, and 4, so I can trust them as well.
Mike //Not my areas of expertise On Wed, Jul 3, 2013 at 9:34 AM, Georgi Guninski <[email protected]>wrote: > Valdis, > > I see no reason to trust tor. > > How do you disprove that at least (say) 42% of the tor network > is malicious, trying to deanonymize everyone and logging > everything? > > Or maybe some obscure feature deanonymize in O(1) :) > > > On Sat, Jun 29, 2013 at 08:05:17PM -0400, [email protected] wrote: > > On Fri, 28 Jun 2013 23:37:45 -0400, Neel Rowhoiser said: > > > I just stumbled across this and despite its sort of half-assed write > up, I > > > think its possibly an advisory? If I am understanding it correctly, > they're > > > saying that you can use a directory authority that hands out > invalid/wrong RSA > > > keys for other relays, you can cause decryption to fail and thus > introduce path > > > bias to nodes of the directory authorities choosing by selectively > handing out > > > valid RSA keys? > > > > Oh, it's *that* attack again (as far as I can tell). Some French guys > did a > > proof-of-concept a few years ago that you could do this sort of thing if > you > > subverted a sufficient number of nodes. But keep reading. > > > > > If the bit towards the end about guard nodes is correct, it would seem > to > > > indicate that they can use the semantics for detecting when a guard is > causing > > > too many extend relay cells to fail to cause valid guards to be marked > invalid, > > > and their rogue guards to succeed essentially using tor's semantics > against > > > them and causing the odds that you-re ingress point to the tor network > is rogue > > > to approach 1. > > > > The problem is that you have to subvert a large number of relays to > > do it, in a way that doesn't get noticed.. > > > > > Why aren't the tor relay keys signed? And what other myriad of > documents do > > > > And who would sign said relay keys? They're all essentially self-signed > > already, so what you're looking for is a PKI. And the whole point of > the tor > > system is that nobody involved trusts a central authority. If you've > got a > > good idea on how to do it, feel free to comment. > > > > > directory authorities serve that also don't have integrity controls? > This sort > > > of makes me question the tor projects ability to deliver on any of the > promises > > > they make, as it would seem that a person needs like 3 or 4 rogue > nodes before > > > they could start de-anonymizing users, and the more of them they > introduced the > > > more of the network they could capture? > > > > Actually, it's more like 3 or 4 *hundred* nodes. As I write this, there > > are 3,903 relays connected, 1,218 guard nodes, and 2,396 directory > mirrors. > > > > http://torstatus.blutmagie.de/ > > > > Even if you control 400 of those routers, the odds that any connection > will > > only traverse your nodes is only 0.1% or so. If you have "3 or 4', it's > > literally a one-in-a-billion shot. Assuming a million tor tunnels form a > > day, you'd catch one circuit every 3 years or so. And no guarantee that > > the circuit you caught carried anything you would find useful. > > > > I suppose you could bring up 4,000 tor nodes of your own, to increase > your odds > > of end-to-end control on a circuit all the way to 12% or so. However, > that's > > very much a one trick pony, and probably wouldn't work simply because > people > > would notice the sudden growth before you got enough nodes connected to > do much > > damage. > > > > And using rogue directory servers to improve your odds doesn't help > either. > > Currently, there's a whole whopping 5 'bad exit' routers. You can > improve > > your chances by corrupting stuff so half the exits are bad - but again, > that > > will get noticed when a single-digit number hits three digits. And you > need > > to get it up to 4 digits before you have decent odds. > > > > And yes, the Tor designers are totally aware that this "vulnerability" > > exists - the problem is that all proposed solutions so far are even > > worse (for instance, requiring signed relay keys). > > > > > > > _______________________________________________ > > Full-Disclosure - We believe in it. > > Charter: http://lists.grok.org.uk/full-disclosure-charter.html > > Hosted and sponsored by Secunia - http://secunia.com/ > > _______________________________________________ > Full-Disclosure - We believe in it. > Charter: http://lists.grok.org.uk/full-disclosure-charter.html > Hosted and sponsored by Secunia - http://secunia.com/ >
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