Quantum Cryptography Ready For Wide Adoption?

An anonymous reader points us to an interview with the founder of quantum cryptography pioneer MagiQ Technologies. From the article: "Q: When do you think we'll see service providers offer quantum cryptography services to their end-customers? A: This will happen within one year and we'll see fairly wide adoption within the next three years. We are working with big carriers such as Verizon and AT&T as well as some companies that own fiber networks. The goal is to embed quantum cryptography into the technology infrastructure so it becomes totally transparent to the end-user..." The cost of a pair of MagiQ boxes to implement point-to-point encryption on a 120-km link is $100,000 plus service.

SNAKE OIL!

[LiquidCoooled]

The only way to see if this works is to break the fibre connection and see if it notices.
Oh lookie, the amazing thing is - a normal fucking fibre circuit will notice as well.

There is no quantum tech yet.

This is just going to increase our month subscriptions without giving any benefits, we will still use encryption on every required connection and will still have open holes alopng the way (last mile), so who exactly does it benefit?

I suggest any carrier should pay them with money stored in a quantum envelope. You are certain it contained $100,000 before you sealed it up, if its not there now it must have been intefered with.

Re:

[vertinox]

The only way to see if this works is to break the fibre connection and see if it notices.

What happens if you splice the line and put a repeater in that also reads the data passing through it?

Fiber optics are tappable you know.

You may notice a short downtime...

Re:

[LiquidCoooled]

Thats my point.

If(allDark) showMessage("PANIC: 1337 haxx0rs have broken in.");

Re:

[Amouth]

or you can just bend the fiber and catch what little bit makes it out.. or you could splice in a larger pice of glass like -|- and read it from the edge of the incerted glass - sure you would notice the beem being weaker but that amount depends on the size of the glass inserted - if you are looking up close you only need to divert alittle of the light to read it.. and the link wouldn't ever have to go down for it to happen - fiber is leaky.. just read the leaks or make your own.. no need to read and repe

Re:

[E++99]

or you can just bend the fiber and catch what little bit makes it out.. or you could splice in a larger pice of glass like -|- and read it from the edge of the incerted glass - sure you would notice the beem being weaker but that amount depends on the size of the glass inserted - if you are looking up close you only need to divert alittle of the light to read it.. and the link wouldn't ever have to go down for it to happen - fiber is leaky.. just read the leaks or make your own.. no need to read and repeat

Re:

[orgelspieler]

In true quantum cryptography, you cannot use a repeater. This is due to the Observer Effect. By measuring the quantum state of a particle, you change it. A professor explained it to me back in the 90s, but I can't remember all the details.

Re:

[MrNaz]

It's known as the Heisenberg Uncertainty Principle. It states that with regards to any particle, you can know either its location or its state of motion but not both. This is due to the fact that in order to observe something, you need to "see" it, which requires that at least one photon touch it. If a photon touches a particle, it will impart energy to it, changing its state. Thus, you will know its location, but you cannot know how the photon has changed the particle's state unless you bounce another phot

Re:

[shutdown -p now]

It's known as the Heisenberg Uncertainty Principle.

No, what matters here is the observer effect, to which the GP referred. As for the uncertainty principle, it's about the precision to which you can know a particle's position and its momentum, and the corellation between those two; and the cause of phenomenon it describes is not disturbance of particle during observation [wikipedia.org].

Re:

[Anonymous Coward]

What happens if you splice the line and put a repeater in that also reads the data passing through it?

I don't know, let's ask the NSA: bomb kill president dirty bomb panties assassination murder terrorist nukular boom boom anthrax

Re:

[fbjon]

panties

Just great, now we'll have the whole army after us!

Re:

[somersault]

I thought that was the cheat for a 3 star rating?

Re:

[Neoncow]

I assume while you do this, [organisation using quantum crypto] will have shot you.

Re:

[enbody]

What happens if you splice the line and put a repeater in that also reads the data passing through it?

You cannot reconstruct the quantum state of an individual photon so a repeater isn't possible. In fact, that is the point.

Re:

[m0ok1e]

You don't have to actually splice the line, if you can get physical access to the line you can bend it and with the right equipment read all the data off the line without any interruption of the normal service. There are videos of this being done, where they capture a broadcast on a fiber wire and there is no noticeable difference on the original signal.

Re:

[Mr. Firewall]

...if you can get physical access to the line you can bend it and with the right equipment read all the data off the line without any interruption of the normal service.

Nope. Not with quantum crypto. First, you can't read the data because it destroys the data. Second, it will DEFINITELY interrupt the normal service! (because you've destroyed the data)

There are videos of this being done, where they capture a broadcast on a fiber wire and there is no noticeable difference on the original signal.

Re:

[skarphace]

And that's the problem with quantum encryption: it's far too susceptible to DOS attacks.

Which is why the tech should only be used on networks that value confidentiality more then service. Quantum Cryptography is NOT a technology for the internet and if anyone tries to convince you of that, they're wrong.

Re:SNAKE OIL!

[da cog]

The "data" that is being sent is not classical information, but quantum information in the form of "qubits". Ergo, you cannot intercept and then "read" it in the sense that your post is describing.

Specifically, what is being sent is one half of two perfectly entangled qubits. The fact that they are "entangled" means that if the two people involved each measure their qubit using the same basis, they will always get the same answer.

When you intercept one of the two qubits, you can measure it but in the process you destroy it, and you cannot create a new qubit that is entangled with the one kept by the sender. Thus, the final recipient of the qubit will no longer get qubits entangled with the original sender's, and so even when the two of them measure with the same basis they are no longer guaranteed to get the same result. In fact, on average 50% of the time they will disagree -- equivalent to what would happen if they both just generated independent random strings of bits.

Now you might say: why not have the repeater just generate a qubit such that the recipient will get the same measurement result as you did? The answer is that you cannot do this because you cannot know in advance what basis he will use to measure the qubit. In the case of photons, he could measure it in a horizontal/vertical basis, or he could measure it in a diagonal basis. (For each measurement he will pick one or the other on a random basis.) If you polarize your photon horizontally (which might correspond to a classical value of "0"), then the other guy will get a random result when he measures it in the diagonal basis. You can only hope to guess right 50% of the time.

Part of the QC protocol is to share selected strings of bits to make sure that they are in fact in ownership of a common secret. If these strings differ 50% of the time, then they know that someone was reading them in the middle.

Thus, the whole point of QC is that it is impossible to put repeaters in the middle to intercept the data without this resulting in a detectable error rate in the shared secret.

Re:

[LiquidCoooled]

One question, what magical technology have we got that can transmit and receive these qubits?
(if possible please refrain from using the word laser or photodiode)

I read on their site a wonderful description (here [magiqtech.com] if you are interested):

The interaction between ions and single photons is quite weak; therefore it has to be enhanced by placing the trapped ions inside an optical resonator (i.e. between two very good, suitably arranged mirrors). This leads to a strong coupling between the light field in the resona

Nope, it actually works

[Mr. Firewall]

What happens if you splice the line and put a repeater in that also reads the data passing through it?

Uh, Dude, you need to do a little bit of reading on quantum cryptography.

The whole point is that you can't do that. Well you can do it, but... everything goes "poof".

Troll is almost entirely incorrect

[billstewart]

Quantum Cryptography is established real technology. It's not particularly *useful*, but it's real.

You won't have gaping security holes in the last mile if you buy this stuff - it's designed to work on end-to-end dark fiber. You'll still need crypto for other reasons, and you'll still have gaping holes inside your wiring closets, but last mile won't be a problem. The range of the system is 120km, so if you're trying to connect buildings together that are farther apart than that, you do have a physical security problem you'll need to manage at your repeater locations.

This won't increase your phone bills unless you buy it. It's not a system designed for carriers to put in their network backbones - it's designed for an end-user customer to buy dark fiber service between a pair of buildings and put these boxes on the ends. The carriers generally charge a pile of money for that kind of service, and the more people buying it, the better their economies of scale, so if you're a consumer who's not buying this, that's slightly positive for you.

The carriers won't need to pay them with quantum money - the end customers will need to pay in real money...

Re:

[Beryllium Sphere(tm)]

>if you're trying to connect buildings together that are farther apart than that, you do have a physical security problem you'll need to manage at your repeater locations.

In quantum terms, a repeater is the same as a measurement. If they can run through repeaters, they're not relying on quantum physics for security. If their claims are correct, they're limited to the length of unrepeated fiber.

Problem is, even without the trivial attack that Shamir proposed a decade ago, it's hard to see what real securi

Short answer

[Rob T Firefly]

Quantum Cryptography Ready For Wide Adoption?

Yes and/or no.

Re:

[An anonymous Frank]

Actually, how does it go; you change the outcome by measuring it? So, could we then discover the key, by looking for it? (Yeah, I'm in a silly mood.)

Re:

[Tackhead]

> > Quantum Cryptography Ready For Wide Adoption?
>
>Yes and/or no.

I could tell you, but then I'd have to collapse this wave function that describes your cat.

Re:

[wirelessbuzzers]

I'd have to collapse this wave function that describes your cat.

Is that what they're calling it these days?

Re:

[GnomeChompsky]

OR is already inclusive! You don't need and there.

Re:

[somersault]

Plus, you can't divide and by or.

Re:

[somersault]

I propose mandatoryandority.

Huh?

[jrwr00]

How in the hell does this work? Why can the interfaces just have inboard encryptions?

Re:

[pdbaby]

Assuming you're not Bruce Schneier making a joke, the point of quantum cryptography is to try and bring perfectly mathematically secure encryption to a point-to-point connection. Normal encryption is good enough but not perfect (i.e. given an infinite amount of time and money, you can break any standard encryption algorithm)

The only perfectly secure algorithm is one where the key is:

• The same length as the key (or "never reused, even within the message" if you want to think of it that way)
• Completely Ra

Re:

[ukatoton]

The key is the same length as itself? I believe that's true in all cryptographic forms that use a key

Re:

[Mr. Firewall]

...the point of quantum cryptography is to try and bring perfectly mathematically secure encryption to a point-to-point connection.

Wrong. Quantum cryptography isn't mathematical at all. And it does not rely on keys.

Re:

[fluffy99]

I was under the impression that regular cryptography was used and it was the quantum hocus-pocus that was used to setup and exchange the session keys?

Re:

[kulnor]

You're right, quantum cryptography is a misnomer for quantum key distribution. The difference is that it's based on the laws of physics and uses symmetric key encryption algorithms rather than public key based mathematical method such as RSA that can in theory be broken given enough time to factor a large number. The major threat to RSA are quantum computer as they'll will be able to factor numbers much faster than classic computers. This could happen in the next 5-20 years. Unless you can break (or change)

Re:

[Jesus_666]

What, we just connect every computer to every other computer and buy a couple dozen billion crypto boxes, then everyone will be completely secure when they visit addons.mozilla.org.

Cryptography != Security

[mpapet]

As a component of a broader security system, cryptography is valuable and solves many problems.

History shows that the weak links in systems employing cryptography is usually some other part of the system. DVD's are an obvious example.

Outside of gov't agencies and the mega-corps that service them, I don't see this taking off like the ipod. The PHB's in the banking world certainly won't understand why this is better than the systems they have now.

Re:Cryptography != Security

[mcrbids]

Outside of gov't agencies and the mega-corps that service them, I don't see this taking off like the ipod. The PHB's in the banking world certainly won't understand why this is better than the systems they have now.

Funny that. When I read the price, my first thought was that this would very possibly explode!

It all comes down to benefits vs. cost. When there are billions of dollars on the line, protecting it with a mere $100,000 seems like chump change. And each $100,000 purchase helps prove a marketplace that will then lower costs.

With every new technology, there's an "adoption curve" where the price drops to a point where it makes sense at high economic levels. So the wealthy and the megacorps adopt the technology because it pays to do so. By doing so, the inventor/developer recoups their initial investments into the technology, and it begins to pay to reduce the price in order to encourage a larger marketplace.

Wash, rinse, repeat, and soon the new technology is available at very affordable prices to average people.

This doesn't happen to *all* technologies. For example, general aviation (EG: light, 1-12 person aircraft) is still pretty firmly entrenched in the ranks of the wealthy, for a variety of reasons. All too few people talk about the "family plane". But even in this case, commercial aviation is very reachable by the average Joe, a la SouthWest airlines.

So, to have perfectly unbreakable encryption over a 120 km link for just $100,000? I think that would get the attention of quite a number of large and middle-sized organizations, banks, and perhaps data warehouses.

Re:

[morgan_greywolf]

This doesn't happen to *all* technologies. For example, general aviation (EG: light, 1-12 person aircraft) is still pretty firmly entrenched in the ranks of the wealthy, for a variety of reasons. All too few people talk about the "family plane". But even in this case, commercial aviation is very reachable by the average Joe, a la SouthWest airlines.

\

You can get into ultralights for under $3,000. Granted this is really not "general aviation", but it's definitely affordable to just about anyone with a decent

Re:

[mcrbids]

You can get into ultralights for under $3,000. Granted this is really not "general aviation", but it's definitely affordable to just about anyone with a decent-paying steady job.

I don't know where you are, but the sub-$3,000 ultralights that I've seen look awfully reminiscent of a death-trap. Something that won't leave your spouse a widow starts about $10,000 and goes up fast from there.

Also, ultralights and sport planes have serious limitations - limitations on flight in controlled airspace, over urban are

Fiber costs matter more than hardware here

[billstewart]

Remember that the users aren't just buying the hardware - they also need to get dedicated end-to-end fiber. In some cases, that can be cheap (e.g. you're just going down the street and you can rent conduit and run your own fiber), but if you're buying telco services and going any distance, you're usually going to be dropping a few tens of thousands of dollars a month. In some parts of George-Gilder-Land, it's cheaper than that, but not usually.

There are some economies of scale for the telcos if they start

Re:

[arose]

So, to have perfectly unbreakable encryption over a 120 km link for just $100,000? I think that would get the attention of quite a number of large and middle-sized organizations, banks, and perhaps data warehouses.

Unless you plan to transport huge amounts of data you can have perfectly unbreakable encryption far, far cheaper--a number of harddrives full of randomness shipped once in a while between the locations. Another plus is that guarding a car for 120km once in a while is far easier then replacing 120

And how does this fit in with federal law?

[porkchop_d_clown]

Isn't there a law requiring telecom providers to make their lines available for government monitoring?

Are companies really going to buy "private fiber" or is this really only for DoD use?

Re:

[t00le]

Well,

Providers have to provide an aggregation point or means of access. So it boils down to either a port on the provider side in promiscuous mode (outside of the secure channel) or an imperceptible channel in some form of monitoring mode.

In the case of these end-points it raises a very good question as to how providers would code an interception point into this technology. One would think that taking an uber-secure channel and programmatically coding in a "backdoor" for lawful intercept would be humorous b

I'm sure they could do it.

[Daniel_Staal]

But I'd rather the lines were upgraded to support faster speeds first. That should be a higher priority than embedding encryption into the network. There is little pressing need for better encyption, but more data bandwidth would help a lot of things.

Re:

[TheRaven64]

More to the point, encryption is pretty much worthless unless it is end-to-end. It's fine making a segment of fibre 100% secure, but if that's just the middle hop, and the bits either side are leaky then it's worthless. This kind of thing might be useful for businesses that have their own, private, unswitched, fibre lines, but for everyone else it is just an expensive false sense of security. Until someone builds a reasonable-sized, working quantum computer, mathematical encryption is likely to be better

This isn't about network backbones

[billstewart]

It sounds like you think this device is being made for telcos to put into their network backbones to make them more secure, and you're saying that you'd rather have them upgrade either the network backbones or the access connections to your house? That's not what this is for.

This is a device that security-paranoid end users like banks or governments can buy, to put on the ends of building-to-building dark fiber service that they'd rent from the telcos. The reason a vendor like this would be working with t

Funny thing is

[rbunce]

by definition Quantum cryptography can not be run on real networks were you have to do things like routing.

It's strictly point-to-point.

[porkchop_d_clown]

Worse, they talk about "repeaters" to extend the range past 120km - which is scary, because it implies they are decrypting/recrypting at the repeater.

Can you say "Physical Security"? I knew you could.

Re:

[BeBoxer]

Yeah, I noticed that too. I could be wrong, but I'm pretty sure that quantum encryption is based on measuring the properties of single photons. Any sort of repeater or amplifier is going to replace the original photons with new ones. Even an EDFA or Ramen amp is replacing the photons which enter the amp with (multiple) new ones. Sure, they have identical properties for the purposes of classical equipment, but the quantum properties aren't preserved. That's the whole point. Nothing can interact with the tran

Re:

[raftpeople]

If the repeater decrypts and then re-encrypts the message for further transmission then you can extend the range. Clearly that opens up the problem of tapping into the repeater, but with good physical security it's better than nothing.

Re:

[BeBoxer]

Sure, it's better than nothing. But is it better than a conventional encryption box which you can buy today for much cheaper? And works over any type of link?

Re:

[Bender0x7D1]

You also lose half of your Q-bits at each repeater. Since it relies on the sender and receiver being in-phase with each other, there is a 50% chance they aren't and what the receiver detects is worthless. (Either + or x configuration.) So if we have 3 "routers" we only end up with 1/16 of the key bits originally sent - 1/(2^4) - since we also have to count the receiver as missing half of the bits.

If we are talking a New York to Los Angeles connection, with only 120km per link, we would need at least

Re:

[Chirs]

I wonder if you could build some sort of repeater that doesn't actually "look" at the photons, but rather entangles a new photon in such a way that it aquires the properties of the old photon, while the old photon is destroyed.

Thus, you would preserve the quantum encryption because you didn't actually extract any information from the system.

Seems like it would work from an information theory point of view...not sure how you would do it from a practical perspective.

Hrm.

[porkchop_d_clown]

It's an interesting idea, I honestly don't know.

Re:

[tbo]

Disclaimer: IAAQIR (I Am A Quantum Information Researcher).

Worse, they talk about "repeaters" to extend the range past 120km - which is scary, because it implies they are decrypting/recrypting at the repeater.

Not necessarily. It's possible in principle to build a "quantum repeater", which receives, "purifies", stores, and retransmits qubits without measuring them. By purification, I mean using either quantum error correction, or quantum entanglement distillation in conjunction with quantum teleportation. Su

Re:

[danpsmith]

by definition Quantum cryptography can not be run on real networks were you have to do things like routing.

I don't know, I for one was persuaded by their guarantee that 50% of the time it works, everytime.

Totally useless

[Jimmy_B]

In practice, quantum cryptography doesn't achieve anything that regular crypto systems like SSL or ipsec don't. Quantum cryptography is theoretically unbreakable, whereas SSL is believed but not mathematically proven to be unbreakable. In either case, it's easiest for an attacker to compromise one of the endpoints, so it's not a big difference. SSL is cheap, easy and widely deployed. So why would anyone spend $100,000+ per link on untested quantum cryptography hardware, when you could roll out ipsec much more cheaply?

Re:

[udderly]

Step 1. Introduce unnecessary product with the words "quantum" or "nano" in it.
Step 2. Get someone to post it on slashdot.
Step 3. ???
Step 4. Profit!

Re:Totally useless

[Chirs]

The benefit of quantum cryptography is in secure key exchange. With regular systems you don't know if someone is sniffing the packets going through your fiber.

With quantum key exchange, the very act of diverting a photon to "sniff" it disturbs the signal enough that the far end can detect it.

Once you've exchanged keys (at a low bit-rate) you then use standard encryption techniques to exchange the actual data.

Re:

[jomama717]

I was about to post the same thing after reading this [magiqtech.com] from the "MagiQ" website, linked from the article. The paragraph entitled "Quantum Cryptography" is very informative, assuming it is accurate.

Re:

[bcrowell]

Once you've exchanged keys (at a low bit-rate) you then use standard encryption techniques to exchange the actual data.
Correct me if I'm wrong, but doesn't this imply that the hardware this company is selling is completely useless with standard protocols? Using TCP/IP and SSH, for example, I assume there's no way to arrange to do the key exchange over one physical connection, and then switch to a different one for the actual exchange of data.

Re:

[jomama717]

From what I gathered in the article and from the company's website I think any deployment would involve two boxes, on at the sender's end and one at the receiver's end, and all communication would be between those boxes using their own protocol. For example a supplier may have a particularly paranoid retailer that requests the use of this technology for all purchase order information. I've done jobs at companies that used dedicated lines for some trading partners in the interest of security, I think this

Re:

[bcrowell]

Hmm...OK, but then I have a hard time understanding the threat they hypothesize on their web site. The threat they talk about is that bad guys do packet sniffing, and record all the packets, anticipating that when quantum computers become available, they'll be able to decrypt them. If you're using a dedicated line, I don't see how that scenario works.

Re:

[jomama717]

Yeah, not sure either. I imagine the companies that I worked at that did use dedicated lines did so as an alternative to using fancy protocols (AS1,2,3, sftp, etc.) so the benefit of the quantum encryption is suspect, I agree. Either the fiber optic line can still be shared or this product is relying entirely on its novelty (oooh... quantum ) for its success.

Re:

[Beryllium Sphere(tm)]

Key exchange in the presence of an eavesdropper is a solved problem already.

Don't waste resources reinforcing the strongest link in a chain.

Re:

[fabs64]

If you're talking about using public private pairs then it's not a solution because they are provably breakable, just not practically.

If you're not, then what are you talking about?

Also PP pairs can be beaten by a true man in the middle attack

Re:

[aetherworld]

Oh no my friend. Quantum cryptography is for when quantum computers are actually available. Quantum computing eliminates the problem of prime/integer factorization so a quantum computer can break SSL within seconds.

That's no longer a mathematical problem but a physical problem then.

Re:

[bcrowell]

OK, so this company will sell a big ISP a way to build a line that's immune to theoretical future attacks using quantum computing. The problem is that it costs a large amount of money, and those attacks are only theoretical. Their web site says the threat is that someone could collect a large amount of SSL-encrypted data, then decrypt it someday in the future using a quantum computer. Well:

1. Most criminals aren't in the habit of undertaking gigantic economic efforts for uncertain returns at some unknown da

Re:

[aetherworld]

Who said you should buy it now? But once a quantum computer is finished, someone has the tool to decrypt all information ever encrypted with RSA (which is based on the fact that prime factorization cannot be solved with an acceptable O() complexity). That includes PGP, GPG, SSL.

Better safe than sorry.

Re:

[E++99]

Oh no my friend. Quantum cryptography is for when quantum computers are actually available. Quantum computing eliminates the problem of prime/integer factorization so a quantum computer can break SSL within seconds.

Sure, unless it turns out to be impossible.

That's no longer a mathematical problem but a physical problem then.

But right now, breaking quantum cryptography is a physical problem, not a mathematical problem. It's based upon the presumption that a photon cannot be detected without disturbing it.

Re:

[scoonbutt]

Amen. This is definitely "security by obscurity", since the quantum physics involved are obscure to pretty much everyone, including the people builing the encryption! Integer factoring is obscure, too, but it's been obscure for a very looooong time.

SSL is quite breakable

[ab762]

as it relies only on being intractable. Throw enough (quantum) resources at it, and it is directly breakable. The fact that on average it takes CPU-centuries is irrelevant to "unbreakable".

Re:

[ifoxtrot]

I don't tend to be particularly picky, but talking about SSL as though it is an encryption algorithm is a tad inaccurate.

SSL is a protocol which can make use of a wide variety of different encryption algorithms in different manners. There's an asymmetric encryption element, mainly for authentication & session key exchange, and a symmetric encrpytion element for the secrecy of ongoing communications. Talk about "breaking SSL" is somewhat misleading -- I think talking about breaking RSA, Diffie-Hellman, D

Re:

[ab762]

Absolutely - you can even configure SSL to use no encryption at all.

In Other News ...

[Diglielo]

Founder of quantum cryptography company predicts widespread adoption within three years.
Inventor of Segway predicts widespread adoption within three years.
Executive of personal hovercraft company predicts widespread adoption within three years.
Early investors in free energy scheme predict widespread adoption within three years.

Re:

[Harmonious Botch]

Yes...but he looked at it. So now its going to happen.

Re:

[sgt.greywar]

Indeed this reeks of a developer trying to market an unfinished and unrefined "product" that no one actually needs just yet.

More Than One Way To Do It Again

[Doc Ruby]

Perl already does QM programming [cpan.org]. Maybe the entanglement timemachine experiment in Spring 2008 will have been successful, and Perl hackers willam haven been sending code through the loop back to the 2002 CPAN?

Quantum Crypto does not solve anything!

[tradeoph]

I can't stand all the hype around Quantum Crypto. If you have a close look at it, you'll see that it doesn't solve anything...

When you transmit bits with QC the law of physics guarantee that nobody will see them, even if some genius breaks all the math behind classical crypto. This is all very well but the throughput is too low, thus QC is used to transmit a key which is then used to encrypt the data. Thus you still need symmetric crypto to encrypt your data.

Now, something everybody seems to ignore: QC does not authenticate the transmission. I can buy two magiQ boxes and set up a man in the middle attack. QC can not prove whether you are exchanging bits with the original sender or with some monkey in the middle. To solve this problem the QC vendors suggest:

• Physical monitoring of the fiber: if you can guarantee nobody touches your fibre, you don't need any crypto!
• Using certificates: Ooops, so now we need asymmetric crypto too, so our QC system relies both on symmetric and asymmetric crypto. Why do we need QC for then?
• Use a shared secret that is programmed into the boxes when they are delivered: If you already have a shared secret, you don't need to exchange a key with QC, you can derive the key from your shared secret...

So even if you use QC, you still need to rely on all the classical crypto to make it work. So it is just as good as classical crypto, without routing.

Re:

[marcosdumay]

Well, the shared secret does not really work. But it's being pushed by the same people that hype QC...

Re:

[LiquidCoooled]

Your analysis corresponds with what I said right at the start, snake oil.

The principle of sending a single photon down the tube and ensuring nobody can measure it without effect is well understood, however there is no method currently to send a single photon down the 120km tubes.

These magic black boxes have to rely on other information to know whats happening (Signal strength, signal variation, timing etc).

Security by obscurity is no substitute.

If it really was a magic box, the whole 120km could be out in t

You're argument is incorrect

[wwwrench]

I had mod points, but what the hell, this is an important point....

You are correct in pointing out (as most responsible qcrypto people do), that qcrypto needs authentication.

However, your argument doesn't follow


So even if you use QC, you still need to rely on all the classical crypto to make it work. So it is just as good as classical crypto, without routing.


The reason is that:

1) The authentication only needs to be secure for a second or two. I just use it foil a man-in-the-middle-attack or authenticate pa

Re:

[Rich0]

So, if I use public key authentication, and the public key is then cracked, no problem, I've already used it to authenticate. The cracked key is now useless to the attacker.

Only if you can generate and communicate securely a new public key every time the link goes down. I guess it is possible in theory. Also - this assumes that you can't crack a public key in realtime - unlikely but theoretically possible. If an interceptor can crack asymmetric crypto quickly enough then you won't be able to spot him.

If

Re:

[lakiw]

I think I remember reading that MagicQ uses a second data channel for authentication that is not "encrypted" by quantum cryptography, (it's closer to steganography than encryption). The quantum channel has a 50% loss rate due to the craziness of quantom mechanics. In fact that's how they try to prevent replay attacks since if someone sniffs it they only see 50% of the data, and when they resend what they have the receiver see an error rate of 75% instead of the normal 50%, (aka 50% of 50%). The receiver

Re:

[Vellmont]

1) The authentication only needs to be secure for a second or two. I just use it foil a man-in-the-middle-attack or authenticate part of the protocol. So, if I use public key authentication, and the public key is then cracked, no problem, I've already used it to authenticate.

err.. OK. And when you need to generate a new public key (because your original one was cracked) how do you transmit it to the other party? How did the other party get the original public key?

Re:Quantum Crypto does not solve anything!

[da cog]

You post sounds like it is based on a misconception that QC is allowing Alice to transmit to Bob a secret. This is not what is going on at all; rather, a shared secret is being generated that Alice does not even know until the end of the process. In classical crypto, a man could sit in the middle and figure out the secret that is shared between Alice and Bob. In properly implemented quantum crypto, however, this is not possible. The best he could do -- using the very man in the middle attack that you described -- is to have one secret that is shared with Alice, and a separate secret that is shared with Bob, when Alice and Bob both think that they have a secret that is shared with each other. It is unlikely that Alice and Bob would take very long to notice that they are using different keys, given that this would produce garbage in every single message that they exchanged.

It's true that he could then hijack ALL communication channels between Alice and Bob, decrypt messages using one key and then re-encrypt them using the other, but... it would probably be easier just to bribe the people doing the transmitting and receiving to tell him what the messages were. I don't think that most people who are serious about security are claiming that QC is a miricule cure, just that it makes one part of the system much, much more secure.

It might be the case that the benefit is not worth the cost, given that the weakest link tends to be the human element, but this is much different than it being "just as good as classical crypto", or a form of "snake oil".

Re:

[kyb]

Only benefit of QCrypto over classical crypto: It stops evesdropping. Problem: It doesn't stop some forms of man in the middle. All this stuff you've said is true, but I don't think it really contradicts the parent. QCrypto is hyped as being unbeatable, which it clearly isn't. The massive effort you think it would take to hijack ALL communications channels between Alice and Bob, is really not that big a deal- you wouldn't man in the middle the QCrypto link unless you knew the other channel the message is

Re:

[Ernesto Alvarez]

But the point is that no matter how good is QC, all an attacker has to do (provided he cannot bribe an operator or infiltrate a spy) is to buy two of these boxes and set a man in the middle attack.
Assuming nobody does something stupid with keying material in classic cryptography, these boxes are as good as any other diffie-hellman boxes you could buy for much less.

These devices provide a means of not getting your keys compromised because someone had the chance to copy them, but is does nothing else. It has

Re:

[Vellmont]

It's true that he could then hijack ALL communication channels between Alice and Bob, decrypt messages using one key and then re-encrypt them using the othe

I thought this is EXACTLY what a man-in-the-middle attack was. If you have another communication channel that doesn't have an attacker between Alice and Bob, Alice and Bob are always going to figure out that they aren't sharing the same key.

but... it would probably be easier just to bribe the people doing the transmitting and receiving to tell him what

I'm Ready!

[ReidMaynard]

I just ordered my Flying Car today, with optional quantum encryption!

Dumbest idea ever

[saleenS281]

So they're going to spend billions implementing encryption on the wire why? AT&T of all carriers should see what a stupid investment that is. NOBODY in their right mind would trust them with secure data anymore. Cats out of the bag, you help the gov't spy on people. As if I or anyone else is going to believe you won't give the US Gov't special access to unencrypted data. Leave encryption up to the end users.

We already have good cryptography...

[Bugs42]

It's called ROT-26 and I'm using it right now.

Wretched Flaccidity.

[hypoxide]

Great, now hackers are going to need degrees in quantum physics just to steal porn.

Quantum computing and DNF

[adrianbaugh]

Quantum computing cards will be a requirement for Duke Nukem Forever. That's why it's taking so long to ship... So when these become widespread, DNF will surely not be far behind!

Stop the Myth

[rdv]

About half the comments here are on base; some of the others are way out in the weeds. Those who are interested in this topic might like my blog posting at Stop the Myth [blogspot.com]. It includes some links to some relatively sane analyses of what QKD will and will not be useful for. I do expect QKD to be useful at some point, but at the moment I expect its utility to be in restricted settings. Quantum repeaters are a long way off; they are one of my current research topics. They will be useful for general distribu

Long term secrecy

[Ignatius]

I work at a research company which designs, among other things, quantum crypto hardware. One important aspect of quantum crypto is that, once the channel is authenticated, the communication (more more precisely: the establishment of the key) cannot be wiretapped and stored away for later decryption. It's basically a method to strech a pre-shared secret (necessary for authentication) almost arbitraily, which can then be used as one-time-pad to encrypt the subsequent classical communication, rendering it unco

Re: Long term secrecy: there are much cheaper ways

[zielaj]

The point about long-term secrecy is interesting, however, it can be cheaply addressed with classical cryptography, in a provably secure way (NOT depending on any computational assumptions like RSA).

http://athome.harvard.edu/dh/hvs.html [harvard.edu]

You still need more assumptions than with QC, which is why I don't exactly buy this approach, but if you really need long-term security, you might consider this scheme.

As for QC, it is expensive, point-to-point only, and makes sense only if you are worried about somebody brea

Re:

[Ignatius]

from http://en.wikipedia.org/wiki/Hyper-encryption [wikipedia.org]:
"hyper-encryption can be proved to be information-theoretically secure, providing the storage bound cannot be surpassed."

Assuming a limited amount of storage for your adversary is a much more optimistic assumption than the mathematical assumptions underlying conventional encryption schemes and not comparable to the unconditional security provided by quantum crypto. It basically relies on the fact that the rate of both, the entropy source as well as the comm

US Gov't Secret "Super Quantum" bit

[XHIIHIIHX]

Thing is, the Gov't has got a quantum superbit that can monitor the activities of all the other quantum bits. So they don't need the telco's to sniff traffic glue for them anymore, they can get the really good stuff while sitting under cheyenne mountain. That's my theory and I'm sticking to it.

QC of ROT256

[DonZorro]

Quality Control of ROT256 will secure all your information