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Schneier Calls Quantum Cryptography Impressive But Pointless
Posted by
timothy
on Thu Oct 16, 2008 03:27 PM
from the science-fair-project dept.
from the science-fair-project dept.
KindMind writes "Bruce Schneier writes in Wired that quantum cryptography, while an awesome technology, is actually pointless (that is, of no commercial value). His point is that the science of cryptography is not the weak point, but the other links in the chain (like people, etc.) are where it breaks down."
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Developers: Cryptol, Language of Cryptography, Now Available To the Public 140 comments
solweil writes to mention that Cryptol, a 'domain specific language for the design, implementation and verification of cryptographic algorithms,' is now available to the public. Cryptol was originally designed for the NSA. It allows for a quick evaluation and continued revisions, and is available for Linux, OS X, and Windows.
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sure... (Score:5, Insightful)
...but as soon as I release my algorithm which factors the products of large prime numbers in log(n) time, they will be begging for quantum crypto.
Re: (Score:2)
Re:sure... (Score:4, Funny)
Parent
Re:sure... (Score:5, Funny)
factors the products of large prime numbers in log(n) time
That's easy, just use sqrt(n) computers.
Parent
Re: (Score:2, Insightful)
In reality, it's always going to be the "endpoints" that are the problem. We still cannot even know with 99.999% certainty that a transaction to a remote application came from a specific user. We use bloated software with tens of millions of lines of code. Even the best err
Re:sure... (Score:4, Interesting)
Parent
Re:sure... (Score:5, Insightful)
Yeah, but in any commercially useful application of the technology, you're going to have computers at each end dealing with the data once it's decrypted.
That's Schneier's whole point really. The weak link isn't actually sending encrypted data, it's dealing with the data at either end of chain. For the data to be useful, it has to be decrypted at some point in time, and the listener's computer has to know how to do the decryption. An attacker isn't going to attack the encrypted data stream. They're going to attack either the source or the listener, and either get the stored decrypted data, or get the stored encrypted data and the necessary info to decrypt it.
If your total communications network consists only of a encrypted communications line, plus a computer on each end, and both of those computers have no other connection to any other sort of network, and also have foolproof physical security, then maybe the encryption line might become the weakest point. But in the real world, computers are generally interconnected with many others, allowing lots of directions to attack from.
Unless someone comes up with some amazing breakthrough that makes factoring very large numbers trivial, there aren't really any practical cases where the encrypted data stream is the likely target of an attack.
Parent
Re:sure... (Score:5, Insightful)
Taking care of the human and physical security is my business. It's the encryption technology that I can't control / verify. So give me encryption that I can trust and I'll be able to assess my security based on the things that I can control / verify myself. Schneier has no business telling me "your set up is flawed so there's no point in giving you secure encryption." It's for me to judge and all I want is to ensure that no weak links come in from outside my control, i.e. a flawed algorithm or technology.
Parent
Re:sure... (Score:5, Insightful)
He's basically telling that we've reached or are close to the point of diminishing returns, where advances in cryptology (newer algorithms or quantum crypto) can no longer be justified based on the increase in cost for these advances versus the % of attacks on existing crypto.
Parent
Re:sure... (Score:5, Funny)
Parent
Who is they? (Score:5, Insightful)
Quantum encryption seems to fill a very particular niche (point to point communications) and doesn't seem to apply well to common encryption use cases (SSL , email encryption etc).
If public key encryption is broken, quantum encryption isn't going to be a good replacement for it for most things.
Parent
A billion photons... (Score:5, Funny)
Are now running for their jobs.
Thanks bruce.
Re:A billion photons... (Score:5, Funny)
Parent
ummmm (Score:5, Funny)
What a pussy. (Score:4, Funny)
What a pussy.
Parent
Re: (Score:3, Insightful)
Er...
"Bruce Schneier knows the state of Schroedinger's cat?"
Re:ummmm (Score:4, Funny)
Er...
"Bruce Schneier knows the state of Schroedinger's cat?"
Actually, he remains ambivalent until someone asks him.
Parent
Hard to argue with the general point. (Score:5, Interesting)
My (admittedly layman's) understanding is that, barring dramatic advances in factorization algorithms, or extraordinary advances in the computers running them, classical asymmetric key cryptography is more than adequate(plus the convenient advantages of working over data links that aren't spiffy optical fiber).
Re:Hard to argue with the general point. (Score:5, Insightful)
Parent
Re:Hard to argue with the general point. (Score:5, Insightful)
I think your analogy is a little bit off. You've got a front door with a standard lock, a dead-bolt, two chains, and a huge rock sitting behind it for security. Now you're faced with a decision whether or not to upgrade your dead-bolt to a super-duper-heavy-duty-dead-bolt. But, since your wife leaves the garage door wide open 4 days a week and no amount of persuasion will convince her to stop, the decision not to upgrade seems like a no-brainer.
Parent
Re: (Score:3, Funny)
> wife is dead
Lock door.
> you hear a grue scratching outside
Re:Hard to argue with the general point. (Score:5, Funny)
Parent
Re: (Score:3, Funny)
Re:Hard to argue with the general point. (Score:4, Funny)
Made by a big International company - bin Laden Group, based in Jidda.
Works perfectly.
To communicate with you, I am thumping on the walls.
If you are listening, could you please cut a hole in the wall.
An upgrade is necessary - I need air.
Parent
Re:Hard to argue with the general point. (Score:5, Interesting)
Parent
Re: (Score:3, Insightful)
Plus, their power is only predicted to be amazing against
Re:Hard to argue with the general point. (Score:5, Insightful)
Which is worse: a password that you can remember, or changing passwords every 30/60/90 days to a new password such that you can never keep up, and thus need to write it down *somewhere*?
Sometimes, the very processes intended to make us more secure (by forcing a password change regularly) instead make the entire system less secure (because "I forgot my password" too many times and you'll end up out of a job, so better to write it down than to lose your job!).
Sorry, just griping about new policies at $work.
Parent
While I appreciate the spirit of the article... (Score:5, Insightful)
I don't think I need to explain that any further to this crowd.
Re:While I appreciate the spirit of the article... (Score:5, Insightful)
You just spent a million dollars on your uber leet super crypto secure link to transmit your highly classified secret data to your home office. You also wrote the key down on a stickey note on the front of the device and left it posted on your monitor that faces a window. You might as well have used the cheapest encryption available because it isn't a math attack that is going to break it, its stupid user tricks.
Parent
Re:While I appreciate the spirit of the article... (Score:4, Informative)
Parent
Re:While I appreciate the spirit of the article... (Score:4, Informative)
Parent
Re: (Score:3, Funny)
It has been and still is true that adept social engineering can break any security scheme, due to the vulnerability of the people involved.
And unfortunately, if you take the people out of the loop, you're letting WOPR become Skynet.
Re: (Score:3, Informative)
From what I understand, quantum cryptography only prevents eavesdropping by taking a part of the signal. Nothing seems to forbid a man in the middle attack (take all the signal and reproduce it), or eavesdropping at a router location. Am I mis-leaded ?
You're mis-leaded. Or misled, rather.
This is quantum key distribution, which uses entangled photons to send keys. It is not vulnerable to m-i-m attacks because a m-i-m cannot reproduce an entangled photon. Even observing it breaks it... so you can't even monitor communications.
I know what to do (Score:3, Funny)
Re:I know what to do (Score:5, Funny)
This is Bruce Schneier we're talking about. Bruce Schneier can decrypt quantum encryption by giving it a stern look.
Parent
Quantum computing breaks normal encryption? (Score:2)
Solving the wrong problem (Score:5, Interesting)
Encryption is easy. Authentication is hard. Quantum cryptography is a solution of the wrong problem.
Hmm. Sounds Familiar (Score:3)
What Schneier is trying to say: (Score:5, Funny)
Re: (Score:3, Funny)
Are you certain about that?
one less cause of defect (Score:2, Insightful)
As far as I know, Switzerland already successfully tested it during last year's elections by transfering voting data from a few selected stations to the voting headquarters. Given all the problems with voting machines, that's a quite obvious area of application. However
Who are the users? (Score:5, Interesting)
Re: (Score:3, Informative)
If you were the CIA you'd be using AES as that is the US Government standard.
Not news (Score:3, Insightful)
Bruce has said this dozens of times before this, and he's right. Quantum Cryptography (or alternatively, Quantum Key Distribution) has no commercial application today, outside of (maybe) a few paranoid and high-security government applications. But the latter can hardly be much of a commercial application, since the existence of a large government market would send a strong signal that governments aren't confident in existing cryptographic algorithms. That would be a bad signal to send.
Furthermore, QKD networks have issues including side channel attacks, where the machinery for transmitting/receiving photons actually leaks information via EM emissions, measurable power consumption, or even sound. In fact, one of the big issues they've had in research networks is that historically the transmission machinery has been noisy as hell.
It's ok to develop stuff for a small user base (Score:3, Insightful)
About the quantum network demo (Score:5, Informative)
I have been there, and can give my impresson. I think, this is a big milestone for quantum cryptography. This has been the most massive and convincing demonstration of the technology up to the date, nothing like any before. Yet, it seems to have received relatively little press attention.
The demonstration was a conclusion of an European project [secoqc.net] in which several tens of research groups collaborated. The main thing it produced are network protocols for a quantum cryptography network. Several months ago, the plan for this demo was four quantum cryptographic links. However, it was easy to plug any quantum crypto link into the network, so six research groups and one commercial company ended up bringing their systems to Vienna (the latter, idQuantique [idquantique.com], actually contributed three links to the network).
Out of these nine systems, seven performed flawlessly for several days, one worked for half an hour and then died (the secure key produced in the first half an hour was still used by the network; the failure was blamed on a software problem in that system), and one prototype did not quite survive the flight to Vienna (hard disk was trashed by baggage handlers). Given that most of the systems were research prototypes, the statistics actually looks good to me.
Since the network topology [secoqc.net] allowed for redundant paths between most of the nodes, the actual failure of one link and simulated failure of another did not prevent the network from operating. (The network topology on the picture as not quite complete: at the last moment, eighth link and one more node were added off the topmost node.) During the demo, there were shown securely encrypted video links between the nodes, and telephone calls. The video links were encrypted with AES with session keys provided by the network. The telephone calls were encrypted with one-time-pad provided by the network. Resiliency to failures was demonstrated: one link was broken on purpose (eavesdropping was simulated by inserting a polarizer, I think), and a key store in another was exhausted during one of the one-time-pad encrypted telephone calls. In both cases, the key distribution was automatically re-routed through other paths and nodes.
The network software implemented so far requires all nodes be trusted and secure. However, I know that algorithms are under development that would allow secure key distribution in a bigger network where up to a certain percentage of nodes might have been compromised.
The demo was on the first day of the meeting. The other two days were just a very good research conference, with no press attending. (I apologize if I got some details above not fully correct.)
Regarding Schenier's position, I respect it but it might be too short-sighted and grounded. And pessimistic. Remember the famous sayings how many computers the world has maybe a market for (five), 640 kB should be enough for everybody, and so on. Classical cryptography has a nasty property to be retroactively crackable. One can record the encrypted classical communication now, wait until it is broken, decipher. Puff, your old secret is suddenly public. For some types of secrets, this is just not an option. Also, Schenier conveniently misses the fact that one can use one-time-pad with quantum key, the combination IS unbreakable, and quantum key distribution speeds steadily improve.
A final remark, there appear to be three commercial companies actually selling quantum key distribution equipment:
The point of pointless research (Score:3, Insightful)
...is actually pointless (that is, of no commercial value)...
It's an interesting definition of "pointless" he's got there; symptomatic of the ultra-capitalistic mindset that has just been demonstrated to be far from optimal by the current financial crisis. Look at it this way: He is saying that the only thing that matters in the world is whether you can make a profit. This is the ideological basis for such things a the lack of regulations that have brought us the crisis; it is also the reason why making a fast profit has been giving priority over long-term financial stability in so many companies, banks not least.
Apart from that - basic research is not pointless, even if there are no short-term profits to be made. Basic research is necessary because we are not able to tell what we are going to need to know in the future - take the early research into quantum mechanics. It was basic research, utterly pointless according to this definition, but we wouldn't have semiconductors today, and thus no PCs nor the endless numbers of electronic gadgets we have now, were it not for that "pointless" research.
It really is time to stop dreaming about "the market" as something magical that will sort everything out for us without requiring us to think and take responsibility.
Re:Quantum Key Exchange not Quantum Computing (Score:5, Informative)
That's what I was thinking as I read a bunch of these posts. The only thing quantum computing and quantum encryption have in common is the word "quantum."
Quantum computers use the superposition of states to form qubits used to do computations using multiple numbers at the same time.
Quantum encrypting uses polarization of light and different alignments of filters to communicate a shared key used to encrypt data. If someone's listening in, they will disturb the polarization causing red flags to go up during the communication of the key. That tells you it's not safe to transmit the message. Furthermore, even if you did, it would just be garbled anyway.
The downside to quantum encryption is that you have to have an uninterrupted fiber optic line from one point to the other. If, at any point, that line has to go through a switch of some sort, you now have a weak point in the encryption where someone can be listening in without you knowing.
It's probably important, too, to point out that we have both quantum computers and quantum encryption. However, the current quantum computers don't have nearly enough qubits to be a threat to public key encryption and the single fiber optic line constraint of quantum encryption is holding it back.
Until quantum computers have thousands of qubits and are easily obtainable, we don't have much to worry about anyway.
Parent
Re: (Score:3, Insightful)
Re: (Score:3, Funny)
Shut your mouth!
I think you need to read some facts about Bruce Schneier!
http://geekz.co.uk/schneierfacts/ [geekz.co.uk]