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The Clock Is Ticking On Encryption
CWmike writes "In the indictment that led to the expulsion of ten Russian spies from the US in the summer of 2010, the FBI said that it gained access to their communications after surreptitiously entering one of the spies' homes, during which agents found a piece of paper with a 27-character password. The FBI had found it more productive to burglarize a house than to crack a 216-bit code, despite having the computational resources of the US government behind it, writes Lamont Wood. That's because modern cryptography, when used correctly, is rock solid. Cracking an encrypted message can require time frames that dwarf the age of the universe. That's the case today. 'The entire commercial world runs off the assumption that encryption is rock solid and is not breakable,' says Joe Moorcones, vice president of information security firm SafeNet. But within the foreseeable future, cracking those same codes could become trivial, thanks to quantum computing."
only if you don't actually want to crack it, then quantum encryption will unlock itself, however if you want to crack it you can't.
i thought once I was found, but it was only a dream.
Many of us have known it for a long time, but more and more people are waking up to the fact that "cloud computing" is a sham. It's basically 1970s-era mainframe computing revived and renamed, with a layer after layer of marketing bullshit layered on. It has all of the same drawbacks as mainframe computing plus some, and often without many of the benefits.
"Quantum computing" risks becoming the next such mania. Soon enough, some marketing dipshits will come along and relabel some lousy existing technology as "quantum computing" (even when it absolutely isn't). This will get the press going, and soon the buzz will be overwhelming. Every manufacturer will be hard at work putting "Quantum Powered" stickers on the hardware they sell, and all sorts of software providers will be labeling their software as "quantum-compatible".
If it's anything like cloud computing has been, it'll just be a waste of time and money.
Yeah, that's true.
Wait, who didn't know this already? The title is misleading, but the fact that quantum computing breaks RSA is pretty standard knowledge (among people who have heard of quantum computing at all, I guess). Of course, there are other encryption schemes that seem to work just fine (e.g. Elliptic curve cryptography) with quantum computing, and there's not much evidence that algorithms other than RSA are broken. Note: factoring isn't NP-complete! So far there's no reason to believe it's not an "easy" problem, except that we haven't figured out how to do it. More intersetingly, there's a lot of research being done on quantum cryptography, which is really quite cool. In total, quantum computing should probably give us more security than it breaks, except for the idiots who keep using outdated algorithms long after they're broken, but they'd be screwed anyway.
So, the sky is falling! Oh wait, no, that's just the weather changing.
I rely on magic pixie dust found on top of the space elevator. It's easier to get than a useful quantum computer and will be for quite some time.
Anyone prepared to take a bet that the CW of CWMike stands for ComputerWorld, and this is a blatant attempt to drive traffic towards an article he either wrote or published?
That kind of behavior, burglarizing houses, committing a crime to stop other crimes, is destructive to the rest of the nation.
I don't find it such a bad thing, if they have a warrant from a non-corrupt judicial system.
You can hardly say fighting espionage is inherently corrupt.
Sheesh, evil *and* a jerk. -- Jade
If you want real security, go with a one-time pad and read up on the mistakes the Kriegsmarine made that let their nifty device get cracked.
Sheesh, evil *and* a jerk. -- Jade
Yes it will. Just because the encryption is "quantum" does not mean it's not trivially breakable with rubber hose cryptanalysis.
Admit nothing. Deny Everything. Make Counter-accusations.
Quantum computing is probabilistic, it has a chance to converge on the right answer, and it gets there in the fairly specific case of using a quantum version of a fourier transform to factor large primes. If you base your crypto method on something not vulnerable to to a quantum fourier transform, or if, with your decryption method you absolutely must get the right answer, you can end up back at brute force.
Quantum cryptography is really not related to quantum computing all that much. They both rely on entanglement, but trying to extract some quantum state of two entangled things (nuclear or electron states most likely) isn't really a computational problem that computing, quantum or otherwise exists to solve. There are lots of practical challenges to quantum cryptography, the short version of which is that a single thing in a specific quantum state is hard to pin down, but lots of stuff (polarized light, atoms in excited states etc.) all happen with a distribution of states. If you were to communicate inside a device this limitation isn't really a problem, but if you need to send data from New York to LA it's very hard to send a single photon or atom (at least for the moment), and if you're sending a million photons, in some collection of quantum states it's somewhat harder to guarantee security. I'm being a bit handwavy here, but a few years ago I did a simple demo quantum crypto project with polarized light, for a couple of hundred dollars in hardware borrowed from an optics lab for an afternoon it worked pretty well. Over the length of a table. Scaling up to fibre optics that move any meaningful distance isn't impossible, but if done wrong you end up rapidly defeating your own crypto system.
For those who don't know, a quantum computer can factor products of primes in polynomial time, with a certain probability of success, but right now because you can't build quantum computer which more than a few qubits you are limited to trivial problems. If you could build a multi-million qubit system you could, with a certain probability of success, factor large products primes such as those used in cryptography in polynomial time.
People generally mention that quantum computing will spell the doom for current crypto, but from what I read on different sites, it seems that it's not exactly that. So I would really appreciate if somebody could clarify it. For instance, on Wikipedia there is this:
So, the problem is only for public key crypto, and for AES we just switch to 512 bit keys and no problem? Also if quantum computers don't do all that great against AES, wouldn't be it just a problem of finding somethinig else they have trouble with that could be used for public key crypto?
But within the foreseeable future, cracking those same codes could become trivial, thanks to quantum computing
At least the number of burglaries will go down
politicians are like babies' nappies: they should both be changed regularly and for the same reasons
Quantum computing could break known asymmetric cyphers, not symmetric. I'm not aware of any quantum solution to breaking any modern popular symmetric algorithms.
Also worth mentioning is that there's really no way the FBI could have known exactly what they'd find. They broke into a home and recovered lots of information, one piece of which proved useful to decrypting messages. If they hadn't found that, who knows what they would have done? Point is don't lower your guard yet - this isn't proof that encryption is rock solid so much as evidence in that direction.
In the end, let's assume unbreakable encryption is readily available. The weakness is in the human factor, since (ultimately) humans have to, at some point, interact with that encryption for it to contain useful information. Looking at the direction England and other countries are going, a government's solution isn't to invest in supercomputers to attack the cryptography; it's to create a set of laws criminalizing a failure to decrypt. Such a failure would be penalized by as much (or more, given the absurd magnitude of criminal damages associated with most modern electronic-targeting laws) as the charges against you for which the cyphertext is relevant. Your information could be protected until the end of the universe while your corpse rots away for some form of electronic obstruction of justice.
There is a pervasive attitude of "If you have done nothing wrong, you have nothing to hide" that seems to be driving a lot of the thrust behind modern laws and solutions. A jury could be (and has been) biased against you just for possession of encrypted material. Why would a legitimate person need to encrypt their documents? Why wouldn't they decrypt them for authorities? "Because they're mine, not yours, and not the government's" isn't something a lot of people sympathize with. I suppose the point I'm trying to make is, while progress on the cryptographic front to stay ahead of authorities (and "bad guys", and the intersection of the two) is critical, it's also critical to enforce a right to innocently encrypt data in the first place.
But sorry to be predominantly negative - overall, a great article that exposes the world of cryptography (and its importance) in terms a layman could understand.
For one, AES is designed to have fixed key sizes, so "just switching to 512 bits" is not as trivial as you may think. Also, not all public key cryptosystems are based on the RSA problem.
Quantum computers can factor the product of two prime numbers in polynomial time, so RSA would be broken. A modification of that algorithm allows certain cases of the discrete logarithm problem to be solved efficiently as well, so DH and ElGamal would be broken also. Luckily, quantum computers are not yet known to be able to solve NP complete problems in polynomial time, so cryptosystems based on NP complete problems (Polly Cracker systems, for example) would still be secure assuming that P != NP. There are also hard lattice problems which quantum computers are not known to be more efficient at solving, which can be used to construct cryptosystems, and there was an early public key cryptosystem based on a group theoretic problem which is known to be secure against quantum computing.
So basically, quantum computing is not really a problem at all, at least not in a theoretical sense. It throws a bit of a wrench into some standard hardness assumptions, but nothing too bad.
Palm trees and 8
Thing is, much of the time you can be pretty sure that a particular string of plaintext will appear at least somewhere in the decrypted result.
In the case of your credit card number, for example, there's a few things we can do to eliminate most of the apparently valid numbers:
I have an algorithm that lets me factor any number with runtime complexity O(1) with a probability 1/(2^log2(n)) and can run on any system with support for /dev/random. No need for expensive quantum hardware. Preliminary tests have been able to break 4-bit RSA quite reliably. Encryption as we know it is doomed.
Where should I go to collect my grant money?
PS: You can leave the Nobel Prize next to my garden gnome. Thanks.
And they'll break any law to accomplish the mission. The FBI has murderers and serial killers who are confidential informants. They also have thieves who are confidential informants.
It's a surprise to me that some Russian spies who you'd expect would be trained to deal with counter intelligence would be so careless.
However not all encryption algorithms can be cracked using quantum computers. The quantum computer cracking of encryption relies on the factorization algorithm and prime numbers but if an encryption is based on another technology the quantum computers aren't a help.
So the Navajo code talkers are still safe.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
Then you get stupid password systems which state your password must be "at least 6 letters, including 1 upper case and 1 number", about 38 bits. Or even worse "between 6 and 8 characters".
Those systems are generally not trying to protect against people with direct access to the encrypted data files. Instead, they are *login* passwords for systems where attackers do not have direct access to the protected data.
In principle, each of those systems should detect repeat login failures and delay or deny further attempts. In that case, the attacker doesn't get to try countless thousands of guesses. Security holes are very common in those types of systems, but it's not necessarily just because the password is 8 characters long.
I rather think that the FBI is quite careful to check that you are not in the house before they go in. They probably have someone trailing you who will warn them if you start heading home or if they lose track of where you are. They are not idiots and have no interest in getting into a firefight unnecessarily.
Basically, stop being stupid. The FBI is not going round breaking into people's houses willy-nilly. They entered those specific houses because they had probable cause to believe that their occupants were hostile agents of a foreign power engaged in illegal espionage, and they had acquired warrants to do so, supported by oath and particularly describing the places to be searched and the things to be seized. Are you seriously complaining because government agents obeyed the Constitution to the letter in the course of exercising their duty to uphold the rule of law?! I can scarcely believe that any American would display such contempt for the principles on which your hard-won freedom is founded.
A couple of thousands do (about 5 times the lenght of the number you want to factor). But what you really need is the ability to perform multi-billion gate-operations (while the QFT itself is quadratic, Shor also uses modular exponentiation which makes it a cubic O(n^3) algorithm) within the decoherence time (usually measured in milliseconds or seconds) and with a technical accuracy to the tune of 99.9999999% - a quantum computer is, after all, an analogous device: qubits don't "lock in"; a NOT-gate e.g. thus has to be an exact 180 deg; rotation and neither 179.999 nor 180.001 deg (does not matter for a couple of gates in toy problems but those imperfections add up).
Quantum error correction can somewhat mitigate the former problem (at the cost of about one order of magnitude overhead in both space and time) but not the later. So if it's feasible at all (which is by no means certain as there might be hidden constraints on scalability), we probably won't live to see it.
ignatius
So, the problem is only for public key crypto, and for AES we just switch to 512 bit keys and no problem?
Not necessarily. At present we know of a small number of quantum algorithms for problems such as factorization and database search. There are some brilliant theorists working on these things, but the total amount of (wo)manpower being applied to these problems is constrained by the fact that we don't really have any quantum computers to use this stuff with. A consequence of this is that there are vastly more problems for which we don't have a quantum algorithm than those for which we do.
This has led to a lot of interest in 'post-quantum cryptography' and flood of research papers proposing new public-key cryptosystems based on mathematical problems we don't know how to solve with quantum computers. Another poster mentioned the McEliece cryptosystem, which is based on problems in coding theory. That's a little bit old-school. The new hotness is lattice problems --- go to any top academic crypto conference and you'll see a bunch of papers using these. If you're really interested in this stuff, here's a pretty good intro to a book on the subject of post-quantum crypto.
However, all this talk is good for researchers in non-standard areas, but it shouldn't lead anyone to be overconfident that these problems will stay resistant to quantum solutions. You can more or less bank on there being some future 'golden age of quantum computing theory' which should take off right about the same time useful quantum computers become available. Predictably, the problems that receive the most attention will be the ones most widely used at the time --- including the ones underlying the most widely used cryptosystems.
The one other thing I should mention is that there's a big difference between finding quantum algorithms for fundamental problems such as database search (Grover's algorithm) or number theoretic problems (Shor's algorithm) and finding quantum algorithms for extremely complex specialized systems like AES. Finding an algorithm that solves a major number theory problem is a big contribution --- if you break a particular cryptosystem, people will just shift away from it eventually and your work will become a footnote. Simultaneously, developing an algorithm that attacks AES is enormously harder using the relatively primitive techniques we currently have. So while right now our best approach to breaking symmetric algorithms is to use generic tools like Grover's algorithm, that's not aways guaranteed to be the case.
Of course, crypto's important to us and the chance for a quantum-resistant cryptosystem is better than none at all, so this is still useful work. If you care about your crypto you need to this stuff it all with a little grain of salt, and hope that QCs are far in the future.
Hash functions and symmetric ciphers are somewhat safe against quantum computers. A quantum computer can give a significant speedup, but only to the point of reducing the strength to half the number of bits it would otherwise have. So, just design the algorithms to work with twice as many bits as needed to break them on a classical computer, and they will most likely be secured against a quantum computer as well.
However public key encryption schemes (especially those built on factorization like RSA) can be broken much faster on a quantum computer. For those just increasing the key length isn't sufficient to give you the edge you need to protect against quantum computers. Research is happening in the field of developing public key schemes that are secure against quantum computers, but I don't know what the current state of that is.
There is a major difference. You don't need a quantum computer to do quantum cryptography. You need a device that can send single qubits, and a device that can receive and measure them. But these devices don't need to work on more than one bit at a time, so they are not really quantum computers. The algorithms do involve a lot of computation, but that computation happens on a classical computer which is doing computation on the data before and after it has been in the state of qubits.
There is a method to increase the range at which quantum encryption can work, which involve quantum computers. You cannot use a classical repeater with qubits because the repeater would collapse the quantum state in pretty much the same way an eavesdropper would. Instead you would use devices that takes advantage of entanglement of qubits. Each such device will require a 2-bit quantum computer in order to work. But a 2-bit quantum computer is no use for breaking any sort of encryption. The encryptions that you could break using a 2-bit quantum computer are much easier to break using a classical computer and a lookup table of all the possible keys.
Do you care about the security of your wireless mouse?