wait... *takes a puff and passes it*
wat?
wat?
y thanks for passing
.... *takes a puff and passes it*eh?
Topic: Quantum Money from Hidden Subspaces (Read 1082 times)
y thanks for passing
.... *takes a puff and passes it*eh?
wait... *takes a puff and passes it*
wat?
wat?
Thanks for your comments.
Somebody sent me a previous paper on the topic:
http://www.scottaaronson.com/papers/noclone-ccc.pdf
and when I went to post it here I put this updated one. Similar material, this time mentions bitcoins.
I like the concept and it is interesting research, but I can't help but think that a lot of the problems he is trying to solve are already solvable in a "classical" manner with digital signatures and a public log-structured database.
Somebody sent me a previous paper on the topic:
http://www.scottaaronson.com/papers/noclone-ccc.pdf
and when I went to post it here I put this updated one. Similar material, this time mentions bitcoins.
I like the concept and it is interesting research, but I can't help but think that a lot of the problems he is trying to solve are already solvable in a "classical" manner with digital signatures and a public log-structured database.
1. There will still be some entity (central or decentral) that will act as the issuer.
Yep, that's part of this research but it isn't obvious that they refer to a decentralized system. They refer to banks and banknotes, essentially suggesting that each bank should issue its own notes. Can confer that idea with gold receipts but it would be preferable to eliminate such counter-party risk, while anyone can verify the authenticity of the notes it doesn't say that the overall supply would necessarily be limited or follow a well understood trend. On the latter point you'd need all the transactions to be transparent (pseudo-anonymous or not) like bitcoin in order to maintain trust. I don't know if they have considered that.
The federal reserve bank and the european central bank are "banks" too. =) I didn't quite get the hint that the authors meant decentralized on a scale that we're more familiar with.
1. There will still be some entity (central or decentral) that will act as the issuer.
Yep, that's part of this research but it isn't obvious that they refer to a decentralized system. They refer to banks and banknotes, essentially suggesting that each bank should issue its own notes. Can confer that idea with gold receipts but it would be preferable to eliminate such counter-party risk, while anyone can verify the authenticity of the notes it doesn't say that the overall supply would necessarily be limited or follow a well understood trend. On the latter point you'd need all the transactions to be transparent (pseudo-anonymous or not) like bitcoin in order to maintain trust. I don't know if they have considered that.
Quantum money usually discusses impossible to forge bank notes and the verification thereof.
There are a few key things that came to my mind regarding quantum money.
1. There will still be some entity (central or decentral) that will act as the issuer.
2. Computational power is not linked to the security of the currency.
Number 2 would be superior to the way bitcoins is done but it also requires that we can send quantum bits through some quantum internet which is still far far far away. Otherwise, the quantum bits have to reside in the physical notes themselves.
There are a few key things that came to my mind regarding quantum money.
1. There will still be some entity (central or decentral) that will act as the issuer.
2. Computational power is not linked to the security of the currency.
Number 2 would be superior to the way bitcoins is done but it also requires that we can send quantum bits through some quantum internet which is still far far far away. Otherwise, the quantum bits have to reside in the physical notes themselves.
My first fear was that they hadn't heard of Bitcoin, but on the first page of their paper they make a reference to Bitcoin. This wouldn't rule out negligence on their part but (also in the first paragraph) they state that they which to avoid any, and all, third parties. That would include the block chain which is essentially a distributed third party.
This is quite a lengthy document so not sure I'll digest it in a day, but I'll dive into it and see what I find. Good find though.
This is quite a lengthy document so not sure I'll digest it in a day, but I'll dive into it and see what I find. Good find though.
I'm not sure where to put this but I'd like to hear what people think of some of the claims in this paper:
http://arxiv.org/abs/1203.4740
Forty years ago, Wiesner pointed out that quantum mechanics raises the striking possibility of money that cannot be counterfeited according to the laws of physics. We propose the first quantum money scheme that is (1) public-key, meaning that anyone can verify a banknote as genuine, not only the bank that printed it, and (2) cryptographically secure, under a "classical" hardness assumption that has nothing to do with quantum money. Our scheme is based on hidden subspaces, encoded as the zero-sets of random multivariate polynomials. A main technical advance is to show that the "black-box" version of our scheme, where the polynomials are replaced by classical oracles, is unconditionally secure. Previously, such a result had only been known relative to a quantum oracle (and even there, the proof was never published). Even in Wiesner's original setting -- quantum money that can only be verified by the bank -- we are able to use our techniques to patch a major security hole in Wiesner's scheme. We give the first private-key quantum money scheme that allows unlimited verifications and that remains unconditionally secure, even if the counterfeiter can interact adaptively with the bank. Our money scheme is simpler than previous public-key quantum money schemes, including a knot-based scheme of Farhi et al. The verifier needs to perform only two tests, one in the standard basis and one in the Hadamard basis -- matching the original intuition for quantum money, based on the existence of complementary observables. Our security proofs use a new variant of Ambainis's quantum adversary method, and several other tools that might be of independent interest.
Authors seem to be unaware of block chain money or think it is irrelevant?
http://arxiv.org/abs/1203.4740
Forty years ago, Wiesner pointed out that quantum mechanics raises the striking possibility of money that cannot be counterfeited according to the laws of physics. We propose the first quantum money scheme that is (1) public-key, meaning that anyone can verify a banknote as genuine, not only the bank that printed it, and (2) cryptographically secure, under a "classical" hardness assumption that has nothing to do with quantum money. Our scheme is based on hidden subspaces, encoded as the zero-sets of random multivariate polynomials. A main technical advance is to show that the "black-box" version of our scheme, where the polynomials are replaced by classical oracles, is unconditionally secure. Previously, such a result had only been known relative to a quantum oracle (and even there, the proof was never published). Even in Wiesner's original setting -- quantum money that can only be verified by the bank -- we are able to use our techniques to patch a major security hole in Wiesner's scheme. We give the first private-key quantum money scheme that allows unlimited verifications and that remains unconditionally secure, even if the counterfeiter can interact adaptively with the bank. Our money scheme is simpler than previous public-key quantum money schemes, including a knot-based scheme of Farhi et al. The verifier needs to perform only two tests, one in the standard basis and one in the Hadamard basis -- matching the original intuition for quantum money, based on the existence of complementary observables. Our security proofs use a new variant of Ambainis's quantum adversary method, and several other tools that might be of independent interest.
Authors seem to be unaware of block chain money or think it is irrelevant?
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