Most Tor Keys May Be Vulnerable To NSA Cracking 236
Ars Technica reports that security researcher Rob Graham of Errata Security, after analyzing nearly 23,000 Tor connections through an exit node that Graham controls, believes that the encryption used by a majority of Tor users could be vulnerable to NSA decryption: "About 76 percent of the 22,920 connections he polled used some form of 1024-bit Diffie-Hellman key," rather than stronger elliptic curve encryption. More from the article: "'Everyone seems to agree that if anything, the NSA can break 1024 RSA/DH keys,' Graham wrote in a blog post published Friday. 'Assuming no "breakthroughs," the NSA can spend $1 billion on custom chips that can break such a key in a few hours. We know the NSA builds custom chips, they've got fairly public deals with IBM foundries to build chips.' He went on to cite official Tor statistics to observe that only 10 percent of Tor servers are using version 2.4 of the software. That's the only Tor release that implements elliptical curve Diffie-Hellman crypto, which cryptographers believe is much harder to break. The remaining versions use keys that are presumed to be weaker."
a few hours for one key would be good (Score:5, Interesting)
If that speculation is right, that a billion dollars will buy hardware that takes a few hours to break one key, great. That would mean nobody is going to break MY key, and that al Qaeda's keys were broken soon after they started using them. Works for me.
Guess who is funding Tor? (Score:5, Interesting)
Re:well (Score:4, Interesting)
Just use bigger DH, with better cipher. AES-256? Maybe. Twofish? OK.
Bruce Schneier himself advises avoiding elliptic-curve, as being intellectually tainted by the spooks. [theguardian.com]
that's what they want you to think.
Re:a few hours for one key would be good (Score:5, Interesting)
If that speculation is right, that a billion dollars will buy hardware that takes a few hours to break one key, great. That would mean nobody is going to break MY key, and that al Qaeda's keys were broken soon after they started using them. Works for me.
I think you're looking at this backwards; They won't spend any money to break your key because you're worth zero dollars. What could you possibly be doing that would warrant the NSA's interest? You need to understand the organization; They primarily do signals intelligence, and they operate in a support role to other agencies, principally the CIA, FBI, and DHS.
The NSA simply logs the data and holds on to it until and unless something happens that makes analyzing that data a priority. They may record all cell phone calls, but they don't listen to them all. They may record all internet traffic, but they don't review all of it. In order for them to expend resources, there needs to be a reason. You could be using '1 bit' encryption and it would be as interesting to them as '1 million bit' encryption.
In security, your defenses need to be harder to break than the value of the thing being protected. Although Tor's encryption may be insufficient against a government, it is plenty strong for most everyday uses -- getting around corporate proxies, location-locked services (like shows the BBC offers, Netflix, etc.), and for proxying to Facebook. Yes, I use Tor to connect to Facebook... because I don't want them knowing where I am, and my IP address provides a wealth of marketing information to them. I also don't use my real name, but really, the main reason is just to piss in their data collection cheerios, not because I'm doing it to be 'anonymous' or 'super secure'. And this is what most people use Tor for; along with browsing bittorrent sites (though downloading is still direct...), and other things that they may feel uncomfortable with having a readily-accessible record of at their ISP's office (gay porn anyone?).
The NSA cares not for these activities. It's logged all the same, but until they say that, say, "the alias raymorris on slashdot indicated he may be in possession of classified materials" all that data just sits on a harddrive somewhere, waiting to expire. The NSA just waits for the phone call.
That said, a few hours to break one key is pretty petty for accessing your internet traffic or mine, but if Al Quaeda has a hidden service inside Tor they're using to communicate with, a secret website if you will... now those few hours' worth of electricity seem very, very worth it.
You've gotta understand that security is not an absolute; There is no "secure" versus "insecure". There is only no security, and then varying degrees of more security; And good security is when it costs more to break it than the value of the thing being protected. Great security is when that's true and the computer functions the way you expect.
Re:Guess who is funding Tor? (Score:5, Interesting)
According to consolidated financial statements and reports of the Tor Project for the year ending December 2012, US Federal agencies are responsible for nearly sixty percent of funds received by the project. Tor has taken a defensive stand against this, but who knows?
Tor was created by the US Air Force. Surprise, surprise, they still want to fund it. Sooo, why did they create Tor? Well, as it turns out, we've got this massive high speed satellite and ground network we use for military purposes, which basically amounts to a compartmentalized version of the internet. And within that, because soldiers are away from home for months or years at a time, they decided to offer internet access to them. Often they're on board carriers, or deployed in places where a direct hookup isn't really feasible. And they want to make sure that all that traffic isn't pouring out at locations that can be easily monitored... because as much as operational security is drilled into soldiers, loose lips sink ships and all, they're still human. They can screw up.
So they needed some way of giving them internet access without making it pathetically easy for foreign powers to simply tap a couple key routers and see everything any soldier browses (Facebook anyone?)... Enter Tor.
Tor has over 13,000 exit nodes all over the world. And it's expensive to monitor every node. Not only that, but you have no idea where in the Tor network the traffic originated from -- is this J. Random Soldier, or Closet Gay Guy Looking At Porn? Noooobody knows. It wasn't meant to be high security. It's not meant to be totally anonymous; It's meant to make it difficult for small-time players like, say, Iran, to spy on our soldier's personal communications. Because this has happened, and it has killed people; A cell phone left on in a soldier's pocket during an operation led to the death of a half dozen marines when enemy combatants used the signal to figure out when they were leaving base... and they planned an ambush.
So Tor will be funded by our government for the conceivable future, and they have a vested interest in maintaining the security of the network to the point that it would cost an adversary more to 'break' the network than the intelligence value of the soldiers' personal internet browsing.
Does this worry me? Nope. Tin foil hat time? Not a chance. Don't use Tor for high value communications. But then... that goes for the public internet as well. If you want to secure high value communications, you build your own VPN, and then add code to have it transmit/receive at a constant rate to deter traffic analysis. Which, coincidentally, is what most financial institutions these days do.
Re:Guess who is funding Tor? (Score:2, Interesting)
"A cell phone left on in a soldier's pocket during an operation led to the death of a half dozen marines when enemy combatants used the signal to figure out when they were leaving base... and they planned an ambush."
Citation?
You won't find one. Another example; Stealth bombers are really great at being stealthy until they're over the target and open the bomb bay doors. Then they're as visible to radar as flying barns. Which is why usually, ahead of the actual strike, a HARM missile is deployed. It's not actually a missile though, but rather a high altitude bomb that, when released, deploys a parachute and sits over the target looking for active radar signatures. When it finds one, off goes the parachute and on comes GPS-guided death. Well, as it turns out, the frequencies used for radar are the same ones used by microwaves. A fork jammed into the security interlock, door removed, and microwave pointed upwards... looked exactly like a radar site. $10 microwave meets $50,000 bomb. And once the bomb has blown up your $10 microwave, you can flip on your actual radar sites, lock on to the stealth bombers, and shoot them down with relative ease. You won't be getting a citation for that either... partly because that er... problem... has been fixed with newer electronics, but mostly because stuff like that being on the internet really is a matter of national security.
So no, no citation for you. But you can feel free to google for 'operational security' and 'cell phone', and note that every branch of the military has rules about this sort of thing. Those rules weren't created because of an abstract hypothetical... like most rules in the military, they were purchased with blood.
Re:a few hours for one key would be good (Score:5, Interesting)
This is not an hypothetical case. In my last job we were in direct competition with IBM and were exchanging crucial pricing information through email. There has been precedents of ECHELON being used to gain economic intelligence (google "echelon airbus boeing" to learn about that)
Oh please. Every government engages in industrial espionage. The French are so well known for it that CEOs for pharmaceuticals that check-in to local hotels are told not to use the fax machine or internet there, and to keep their laptops in their room, and to bring their own locks to secure it and not use the hotel safe or in-room safe as the cleaning crew often isn't the usual maid service. I mean, this is SOP. Not that I'm picking on the French -- they're only guilty of being particularly bad at doing it covertly, but everyone does it.
One does not need ECHELON to spy on a company. Hell, showing up to replace a printer in slacks and an official-looking work order is usually enough to get into a building... and having a rigged printer that records all the jobs sent to it is a nice opener. Following up with a power strip with its own wifi, mini computer, and cat5 pass-thru is a good follow-on. Why do people assume you need satellites and taps on hundreds of internet routers all over the world to do this?
And don't underestimate blackmail, human stupidity, or the CEO's penchant for keeping a post-it note with his password on his computer, trusting that his secretary and security staff would neeeeever let anyone in who wasn't supposed to be there.... and of course, nobody ever takes bathroom breaks while watching the CEO's office over lunch time.... -_-
And as a bonus... most corporations record all e-mails to monitor their employees. Amusingly... these systems are usually less secure than the ones they're tapped into. So if you don't have the money to bring your own equipment... they're usually nice enough to provide it for you.
Re:Getting tired here (Score:4, Interesting)
Hackers can't afford to be apolitical anymore. It's what brought us to the current situation.