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PirateKing15

Quantum Cryptography

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I don't know exactly how old this concept is or if it is even being used yet. I read a little about it but came here to ask a question.

Is it un-hackable? I know that NOTHING is un-hackable but I read that this concept has physics on its side. If anybody knows any more info on the subject, let me know.

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I don't know exactly how old this concept is or if it is even being used yet. I read a little about it but came here to ask a question.

Is it un-hackable? I know that NOTHING is un-hackable but I read that this concept has physics on its side. If anybody knows any more info on the subject, let me know.

The way I understand it (and believe me, I'm four or five steps below layman), it would take millennia to crack using modern computing methods, but if you were to use quantum computing to crack it you make it possible again. I'm 90% sure I'm wrong, so if someone more educated wouldn't mind, correct me.

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Quantum cryptography makes use of quantum entanglement and quantum teleportation to guarantee secure communication of an encryption key between two parties. Quantum cryptography is only used to produce and distribute the key. It cannot be used to communicate any meaningful data of any sort.

Side note: As opposed to what the name suggests, quantum teleportation can not be used to transfer information at superluminal speeds, nor can it be used to transfer any information alone.

http://en.wikipedia.org/wiki/Introduction_...antum_mechanics

http://en.wikipedia.org/wiki/Quantum_cryptography

http://en.wikipedia.org/wiki/Quantum_computer

http://en.wikipedia.org/wiki/Quantum_information

http://en.wikipedia.org/wiki/Uncertainty_principle

http://en.wikipedia.org/wiki/Quantum_entanglement

http://en.wikipedia.org/wiki/Quantum_teleportation

http://en.wikipedia.org/wiki/Quantum_superposition

http://en.wikipedia.org/wiki/Quantum_mechanics

http://en.wikipedia.org/wiki/No_cloning_theorem

http://en.wikipedia.org/wiki/No-broadcast_theorem

http://en.wikipedia.org/wiki/No_teleportation_theorem

http://en.wikipedia.org/wiki/No_communication_theorem

Edited by chown
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If you can use QC to produce the key, then can't you use it to crack the key as well?

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Only if you the precise location and velocity of a butterfly halfway around the world, can you open the box and discover whether the cat is alive or dead.

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If you can use QC to produce the key, then can't you use it to crack the key as well?

Yeah, that's what I was trying to say above.

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I think DNA computing is currently a far more realistic approach to breaking encryption.

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If you can use QC to produce the key, then can't you use it to crack the key as well?

Yeah, that's what I was trying to say above.

Not any more than you can use a brute forcer to guess the key.

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If you can use QC to produce the key, then can't you use it to crack the key as well?

Yeah, that's what I was trying to say above.

Not any more than you can use a brute forcer to guess the key.

From what I understand, QC is a lot different than brute force since you can look at all the keys at once. Someone please correct me if I'm wrong.

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If you can use QC to produce the key, then can't you use it to crack the key as well?

Yeah, that's what I was trying to say above.

Not any more than you can use a brute forcer to guess the key.

From what I understand, QC is a lot different than brute force since you can look at all the keys at once. Someone please correct me if I'm wrong.

No, one cannot observe quantum superposition.

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If you can use QC to produce the key, then can't you use it to crack the key as well?

Yeah, that's what I was trying to say above.

Not any more than you can use a brute forcer to guess the key.

From what I understand, QC is a lot different than brute force since you can look at all the keys at once. Someone please correct me if I'm wrong.

No, one cannot observe quantum superposition.

Hold on, that has to do with quantum key transmission. I'm not talking in terms of key transfer (i.e. Diffie-Hellman in contemporary terms.) I was referring to key generation; I'm saying that if you can produce cryptographic keys with a quantum computer, then you can crack keys produced by a silicon machine in O(1). You don't have to use brute force in this case since you already know what they all are. So like, if the NSA already has a quantum computer they can instantaneously read a "top secret" document encrypted with RSA 2048-bit, Twofish, or whatever the latest and greatest algorithms and key lengths are for digital computers.. Right?? :skullblink:

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No, one cannot observe quantum superposition.

Until the attacker enters the correct password, the cipher is both PWND and NOT PWND at the same time!

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What if the encryption throws in some bogus words and crap and to get the message, you have to pull out certain words by some prearranged numbering system.. How will quantum computing help crack that?

I guess I am saying.. what if there are multiple layers?

I say the above as a side thought. I have not studied up on crypto and don't know what I am talking about.

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No, one cannot observe quantum superposition.

Until the attacker enters the correct password, the cipher is both PWND and NOT PWND at the same time!

Haha, something like that :P

If you can use QC to produce the key, then can't you use it to crack the key as well?

Yeah, that's what I was trying to say above.

Not any more than you can use a brute forcer to guess the key.

From what I understand, QC is a lot different than brute force since you can look at all the keys at once. Someone please correct me if I'm wrong.

No, one cannot observe quantum superposition.

Hold on, that has to do with quantum key transmission. I'm not talking in terms of key transfer (i.e. Diffie-Hellman in contemporary terms.) I was referring to key generation; I'm saying that if you can produce cryptographic keys with a quantum computer, then you can crack keys produced by a silicon machine in O(1). You don't have to use brute force in this case since you already know what they all are. So like, if the NSA already has a quantum computer they can instantaneously read a "top secret" document encrypted with RSA 2048-bit, Twofish, or whatever the latest and greatest algorithms and key lengths are for digital computers.. Right?? :skullblink:

The short answer is: No, you cannot use quantum superposition to magically select the correct key from all possible values.

This is because a particle exists in a superposition of all possible states while not being observed. Observing it destroys the superposition.

A scientist called Erwin Schrodinger formulated this, making it famous with his thought-experiment involving a caged cat whose life depends on the half-life of a radio isotope, which could completely decay in the time the cat is not being observed and trigger the release of a toxin to kill the cat. Or, with equal probability, it might not. One can only know by observing the cat, which until such a time, exists in quantum superposition of all possible states; i.e., is both alive and dead, and everything in between.

For a more complete explanation, see Schrödinger's cat

schrodingers-lolcat1.jpg

:lol:

Edited by chown
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Yeah, his point was to illustrate what a dorky idea it was.

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In that case, QC seems pretty useless as far as attacking encryption on silicon-based machines, unless I'm missing something. I think I'll stick to my DNAC research.

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In that case, QC seems pretty useless as far as attacking encryption on silicon-based machines, unless I'm missing something.

You're missing the fact that it's much, much faster but the technology is still in early development.

http://en.wikipedia.org/wiki/Quantum_computer

I understand that it's many orders of magnitude faster. I just don't see what the current utility of it is with respect to silicon-based encryption. DNA is much further along which is why I think it deserves more attention; practical attacks have already been executed with it.

BTW, how many times are you guys going to duplicate links to Shittypedia? :lol: lollers

Edited by duper
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There was an article published in IEEE magazine several months ago concerning a man-in-the-middle vulnerability in contemporary quantum crypto systems.

Here's another attack discovered at MIT that allows key observation through quantum entanglement.

To answer the question of the OP, I imagine there'd need to be another great discovery in our understanding of Physical Science and/or Molecular Computing in order to make more attacks against Quantum Crypto feasible.

Edited by duper
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1. As far as I know, the security of quantum entanglement isn't that no one can disrupt your communication, its that if someone DOES observe your communication, the superposition collapses, and the eaves dropping _is detectable_. So, you keep transmitting until the laws of physics guarantee you weren't watched, and that is the best part of it, as far as I understand.

2. Quantum cryptanalysis DOES check many keys at the same time (using superposition). The rules say that if you look at a system in superposition, you destroy it, but if you don't look until the cipher has been cracked, then you harness the power of superposition to execute a search that no classical computer can compete with.

3. Quantum computers AREN'T faster than silicon computers. Classical processors aren't going to be replaced, because what quantum computers don't do exceedingly well, they do at horrible cost. I would guess that a much more likely outcome will be that silicon-based processors will eventually contain 8 quantum-bit cores for performing certain computations.

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1. As far as I know, the security of quantum entanglement isn't that no one can disrupt your communication, its that if someone DOES observe your communication, the superposition collapses, and the eaves dropping _is detectable_. So, you keep transmitting until the laws of physics guarantee you weren't watched, and that is the best part of it, as far as I understand.

What's to keep someone from setting up a box that can read and write these superpositions, connect it to the line in two places, then start observing after the line is cut between the two taps?

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2. Quantum cryptanalysis DOES check many keys at the same time (using superposition). The rules say that if you look at a system in superposition, you destroy it, but if you don't look until the cipher has been cracked, then you harness the power of superposition to execute a search that no classical computer can compete with.

That's true insofar as to allow rapid factoring of large numbers (using Shor's algorithm), which can in theory be applied to break RSA whose integrity is contingent on the computational infeasibility factoring large numbers.

But from what I understand, QC cannot be applied to 'crack' symmetric-key algorithms (AES, Twofish, Serpent, etc) or hash functions (MD5, SHA, RIPEMD, etc).

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2. Quantum cryptanalysis DOES check many keys at the same time (using superposition). The rules say that if you look at a system in superposition, you destroy it, but if you don't look until the cipher has been cracked, then you harness the power of superposition to execute a search that no classical computer can compete with.

That's true insofar as to allow rapid factoring of large numbers (using Shor's algorithm), which can in theory be applied to break RSA whose integrity is contingent on the computational infeasibility factoring large numbers.

But from what I understand, QC cannot be applied to 'crack' symmetric-key algorithms (AES, Twofish, Serpent, etc) or hash functions (MD5, SHA, RIPEMD, etc).

With sufficient speed it could be used to efficiently brute force them.

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