4 ms·

As far as practical implementations are concerned, the Chinese already have a running quantum network between large cities, and are planning to launch a "quantu

As far as practical implementations are concerned, the Chinese already have a running quantum network between large cities, and are planning to launch a "quantum satellite" in June as well. There are companies selling this kind of equipment already, e.g. ID Quantique, so this technology is already quite mature and working. I don't understand why this should not count as a practical implementation. Also, to my knowledge it's the only technology that can (in principle) provide a fully secure key exchange over an insecure channel, and with states like the US investing heavily in quantum computing the possibility of decrypting RSA-based cryptography (and similar method) seems not so far-fetched anymore. Of course symmetric cryptography can be resilient against quantum attacks (as far as we know today) if this keys are sufficiently long, but the problem is to securely exchange those keys, and this is were quantum cryptography has its place (again, in my opinion). I would love to hear why this idea is flawed though, I just don't think that calling the other side "stupid" is a legitimate way of arguing.

acqq 10y ago
> Of course symmetric cryptography can be resilient against quantum attacks (as far as we know today) if this keys are sufficiently long, but the problem is to securely exchange those keys, and this is were quantum cryptography has its place (again, in my opinion). I would love to hear why this idea is flawed though Because security-wise, according to djb claims in the original article (and Schneier too (2)), everything that the "quantum network" does can as well be implemented with the normal insecure internet and the symmetric ciphers, with the same security limitations (the secure channel, as per djb, initially is needed in both cases: "Quantum cryptography, like locked-briefcase cryptography, also relies on a preexisting secure channel (to authenticate choices of "bases" by Alice and Bob)" See also (1) ). So from the security standpoint it's a typical "snake oil" not improving anything but costing more, being much more complicated to maintain and therefore much less secure from the get-go. "The Manifesto says that it is "endorsed by a broad community of industries, research institutes and scientists in Europe" and is accompanied by an online list of thousands of signatories; but the list looks more like a rather narrow community of people who are hoping that the Manifesto makes money for them, such as quantum physicists and their students. Security review, like environmental review, requires experts who are skeptical." 1) https://en.wikipedia.org/wiki/Quantum_key_distribution https://en.wikipedia.org/wiki/Quantum_key_distribution "These proofs are unconditionally secure in the sense that no conditions are imposed on the resources available to the eavesdropper, however there are other conditions required: - Eve cannot physically access Alice and Bob's encoding and decoding devices. - The random number generators used by Alice and Bob must be trusted and truly random (for example a Quantum random number generator). - The classical communication channel must be authenticated using an unconditionally secure authentication scheme. - The message must be encrypted using one-time pad like scheme." 2) "Quantum Cryptography: As Awesome As It Is Pointless" https://www.schneier.com/essays/archives/2008/10/quantum_cryptography.html https://www.schneier.com/essays/archives/2008/10/quantum_cry...
- ThePhysicist 10y ago
  but those requirements apply to the case where the attacker has unlimited classical and quantum computing capabilities. Under those conditions, all classical cryptographic methods fail (except one-time pad), because the attacker can just brute-force any key. That QKD still works under these assumptions is amazing in itself, and in any practically relevant scenario the limitations will probably not matter, as long as the key exchange is fast enough such that no decryption & manipulation of the classical channel is possible. Also, the attacker not having access to the decoding device is a reasonable assumption IMHO, as classical encryption won't do you any good either if the attacker has full access to your computer. All in all, I think that the critique is justified but it is not something that will keep QKD from being useful in the field (I could be wrong of course).
  - acqq 10y ago
    The problem is, from the point of view of that conventional security expert (and of me too) the only "usefulness in the field" is the possibility to sell the extremely expensive snake oil to the buyers who don't ask what the price is. Because even without the same snake oil, the equivalent system can be designed, maintained and be significantly cheaper. Getting money from those who can give a lot can also be a valid economic goal, or in this case an accepted approach to funding (I quoted that Microsoft researcher) but using "snake oil" can still be seen as the evil opposite of the established principles of honest security engineering, the classic entry for Schneier's "doghouse." The fair approach would be, "we're doing the basic research, no there's no too practical applicability of our research, but it's good to fund it anyway, that's why the research is different from engineering." It would also let engineers do their work and not force them to implement less secure directions "because policy." Which is the effect that certainly appears here and there on the EU level.
- deleted 10y ago
  [deleted]
nabla9 10y ago
>I just don't think that calling the other side "stupid" is a legitimate way of arguing. There should not be "the other side". Yet there is no sign of security researches involved making these claims and you seem genuinely surprised that there is controversy and security researchers debunk the claims.
- ThePhysicist 10y ago
  I do not say that there is another side, this is what the article proposes. Also, there is a difference between engaging with someone in a constructive discussion and just ranting against a funding decision. Has the author actually tried engaging with the people involved on the EU side or the researchers working on these systems? Also, saying that there is no involvement of the security research community in the development of these systems is almost certainly not true at least it would be very surprising to me.

acqq 10y ago

> Of course symmetric cryptography can be resilient against quantum attacks (as far as we know today) if this keys are sufficiently long, but the problem is to securely exchange those keys, and this is were quantum cryptography has its place (again, in my opinion). I would love to hear why this idea is flawed though Because security-wise, according to djb claims in the original article (and Schneier too (2)), everything that the "quantum network" does can as well be implemented with the normal insecure internet and the symmetric ciphers, with the same security limitations (the secure channel, as per djb, initially is needed in both cases: "Quantum cryptography, like locked-briefcase cryptography, also relies on a preexisting secure channel (to authenticate choices of "bases" by Alice and Bob)" See also (1) ). So from the security standpoint it's a typical "snake oil" not improving anything but costing more, being much more complicated to maintain and therefore much less secure from the get-go. "The Manifesto says that it is "endorsed by a broad community of industries, research institutes and scientists in Europe" and is accompanied by an online list of thousands of signatories; but the list looks more like a rather narrow community of people who are hoping that the Manifesto makes money for them, such as quantum physicists and their students. Security review, like environmental review, requires experts who are skeptical." 1) https://en.wikipedia.org/wiki/Quantum_key_distribution https://en.wikipedia.org/wiki/Quantum_key_distribution "These proofs are unconditionally secure in the sense that no conditions are imposed on the resources available to the eavesdropper, however there are other conditions required: - Eve cannot physically access Alice and Bob's encoding and decoding devices. - The random number generators used by Alice and Bob must be trusted and truly random (for example a Quantum random number generator). - The classical communication channel must be authenticated using an unconditionally secure authentication scheme. - The message must be encrypted using one-time pad like scheme." 2) "Quantum Cryptography: As Awesome As It Is Pointless" https://www.schneier.com/essays/archives/2008/10/quantum_cryptography.html https://www.schneier.com/essays/archives/2008/10/quantum_cry...

ThePhysicist 10y ago
but those requirements apply to the case where the attacker has unlimited classical and quantum computing capabilities. Under those conditions, all classical cryptographic methods fail (except one-time pad), because the attacker can just brute-force any key. That QKD still works under these assumptions is amazing in itself, and in any practically relevant scenario the limitations will probably not matter, as long as the key exchange is fast enough such that no decryption & manipulation of the classical channel is possible. Also, the attacker not having access to the decoding device is a reasonable assumption IMHO, as classical encryption won't do you any good either if the attacker has full access to your computer. All in all, I think that the critique is justified but it is not something that will keep QKD from being useful in the field (I could be wrong of course).
- acqq 10y ago
  The problem is, from the point of view of that conventional security expert (and of me too) the only "usefulness in the field" is the possibility to sell the extremely expensive snake oil to the buyers who don't ask what the price is. Because even without the same snake oil, the equivalent system can be designed, maintained and be significantly cheaper. Getting money from those who can give a lot can also be a valid economic goal, or in this case an accepted approach to funding (I quoted that Microsoft researcher) but using "snake oil" can still be seen as the evil opposite of the established principles of honest security engineering, the classic entry for Schneier's "doghouse." The fair approach would be, "we're doing the basic research, no there's no too practical applicability of our research, but it's good to fund it anyway, that's why the research is different from engineering." It would also let engineers do their work and not force them to implement less secure directions "because policy." Which is the effect that certainly appears here and there on the EU level.
deleted 10y ago
[deleted]

nabla9 10y ago

>I just don't think that calling the other side "stupid" is a legitimate way of arguing. There should not be "the other side". Yet there is no sign of security researches involved making these claims and you seem genuinely surprised that there is controversy and security researchers debunk the claims.

ThePhysicist 10y ago
I do not say that there is another side, this is what the article proposes. Also, there is a difference between engaging with someone in a constructive discussion and just ranting against a funding decision. Has the author actually tried engaging with the people involved on the EU side or the researchers working on these systems? Also, saying that there is no involvement of the security research community in the development of these systems is almost certainly not true at least it would be very surprising to me.