Talk:Quantum digital signature

Definition Problem
(Anonymous user, 2019-09-01) There is a substantial problem with this article, in terms of definitions. What is described (the Gottesman-Chuang scheme) is not a "quantum digital signature scheme", but rather a "digital-message signature scheme with quantum keys". A quantum digital scheme proper would typically use classical private and public keys, but would allow a sender to sign a quantum state rather than a classical one. Interestingly, it turns out that such feat is (almost) impossible: https://arxiv.org/abs/1811.11858 — Preceding unsigned comment added by 92.104.85.162 (talk) 19:02, 1 September 2019 (UTC)

Quantum secure digital signatures
Just in case the editors of this page doesn't know: There are several old signature schemes that are believed to still be secure in the event that quantum computers are created. One of them is the Lamport signature scheme from the 1970's.

However, as far as I know there are currently no public-key encryption scheme that is secure if quantum computers are created. (That is to encrypt messages, not sign.) But in that case we can use symmetric ciphers and "symmetric key CA systems" similar to the Kerberos (protocol), also invented in the 1970's.

So no worries, we can still securely encrypt and sign messages in the future.

--David Göthberg (talk) 09:56, 22 February 2008 (UTC)

(Anonymous user, 2019-09-01) actually there exist many candidate public-key encryption schemes already (of course none of them has been proven to be quantum-resistant, they rely on computational assumptions, just as RSA is not proven to be classically-resistant). See for example https://csrc.nist.gov/Projects/Post-Quantum-Cryptography/round-2-submissions — Preceding unsigned comment added by 92.104.85.162 (talk) 18:51, 1 September 2019 (UTC)

Overview
I feel like most of the information in this section is rather redundant and its purpose would be better served by linking first mentions in the article proper to the articles about public-key cryptography and one-way functions. Does anyone else have any thoughts on this? CarLuva (talk) 21:29, 29 February 2008 (UTC)

Swap Test
It seems that there's no need to measure all the qubits - only the first one. The figure of the circuit should be changed. Two other suggestions: First, maybe the "swap test" should be in a different page.

Second, I think that an analysis for the probability of getting 0, which is 1/2(1+|<\phi|\psi>|^2) should be given. 128.139.226.37 (talk) 11:46, 9 July 2008 (UTC)

The graph of the swap test seems to be wrong. The right graph is on the fourth page of http://arxiv.org/PS_cache/quant-ph/pdf/0102/0102001v1.pdf — Preceding unsigned comment added by 130.183.93.31 (talk) 10:11, 12 September 2011 (UTC)

= Experimental Demonstration = It seems that Clarke et al. have carried out what is being touted as the first experimental demonstration of quantum digital signatures in Clarke, P.J. et al. Experimental demonstration of quantum digital signatures using phase-encoded coherent states of light. ''Nat. Commun.'' 3:1174 doi:10.1038/ncomms2172 (2012). Should a reference to this be included in the main entry? FloatingThirdParty (talk) 10:29, 19 November 2012 (UTC)