Talk:Quantum key distribution

Kish cipher

I removed the reference to Kish cypher as a "competing classical technique" because I don't see how it can be said to compete with quantum cryptography, notwithstanding Kish's claims. People are interested in quantum cryptography only because there's a proof from basic physical principles of security against certain attacks. Classical ciphers are orders of magnitude faster, cheaper, and more versatile, but we have no security proof for them (though they seem to be secure). The Kish cipher is comparable to quantum cryptography in speed and versatility, and I can't find any evidence that Kish or anyone else has proved its security. So it seems to combine the disadvantages of classical cryptography with the disadvantages of quantum cryptography, and I don't understand why anyone is interested in it at all. -- BenRG (talk) 11:25, 27 September 2008 (UTC)

Quantum Key Distribution

Quantum Key Distribution (QKD) is NOT synonymous with Quantum Cryptography. Using the terms as such is extremely misleading. In the past 7 or so years many Quantum Secure Direct Communication (QSDC) protocols have been proposed which claim to be provably secure. If they are, then QSDC is probably superior to QKD. Some also claim to have solved the authenticated line problem. Google Quantum Secure Direct Communication for some examples. Redsecure (talk) 23:52, 21 March 2009 (UTC)

I've created the page Quantum Secure Direct Communication redirecting to Quantum cryptography. Feel free to add a section in Quantum cryptography or give it it's own article and we can add a note at the top of Quantum cryptography. Skippydo (talk) 03:41, 23 March 2009 (UTC)

FPB attack

(Moved from User talk:BenRG)

I recognized that you roll-backed the contents about FPB attack on Quantum Cryptography. But FPB attack is experimentally prooved on 2006. For more information, please see this(paper about the FPB attack experiment). Or what about to describe like this? "Quantum Cryptography is vulnerable to attacks using QND"
Modamoda (talk) 07:40, 19 July 2009 (UTC)

This attack is just the most general form of eavesdropping on the communication channel. QKD protocols are designed to protect against it. It's an attack on QKD in the same way that chosen-plaintext is an attack on ordinary cryptosystems: it's something the designers know about and protect against so that the attack doesn't work in practice. This experimental test doesn't add much because it just verifies the quantum mechanical prediction, which everybody believed anyway. Quantum mechanics is far too well tested to fail in a simple experiment like this. I have nothing against the paper, but if we added a paragraph about every paper like this to the article it would grow ridiculously long. This attack isn't really using Quantum Nondemolition measurement. Saying that QKD is vulnerable to QND measurement is the same as saying that classical cryptography is vulnerable to someone who guesses the key by sheer luck. It's technically true, but we don't worry about it. -- BenRG (talk) 12:06, 19 July 2009 (UTC)

Thanks for replying. :)
Modamoda (talk) 15:21, 19 July 2009 (UTC)

One Time Pad

I have never suggested anything on Wikipedia before, and I am certainly not an expert on cryptography or quantum cryptography. However, I do not undestand this: "The algorithm most commonly associated with QKD is the one-time pad, as it is provably secure when used with a secret, random key." My understanding of the one-time pad is that it must be (at least) the same length (number of bits) as the plaintext, never re-used, and certainly not computable from any shorter "secret, random key". Unless I am misinformed, the quoted statement is incorrect and should be removed. —Preceding unsigned comment added by 24.78.1.239 (talk) 17:41, 13 September 2009 (UTC)

My knowledge about OTP(One-time pad) is not like that. I think OTPs don't have to have(or generate) same length with the Plaintext.
- Modamoda (talk) 09:52, 14 September 2009 (UTC)

" Perfect data secrecy may not seem possible, particularly if potential attackers are given absurd amounts of time (and can run brute force searches in parallel). But, oddly enough, there is an encryption algorithm that can't be broken if used properly: the one-time pad. What is even stranger is that the algorithm is incredibly simple.

The basic idea behind a one-time pad is that there's as much key material as there is text. The encryption operation can be simple modular addition. In computer-based uses, it is often XOR.

"Here's the simple algorithm for one-time pads: For each plain text message, generate a random secret key. The key should be exactly the same length as the plain text message. The cipher text is created by simply XOR-ing the plain text with the key." (from http://www.ibm.com/developerworks/library/s-pads.html ) —Preceding unsigned comment added by 24.78.1.239 (talk) 22:21, 14 September 2009 (UTC)

Using a one-time pad with QKD is indeed meaningful. And as you point out, a one-time pad isn't computed from a shorter secret key -- basically, you'd use just whatever you got from the QKD. And of course, you'd use each bit of quantum-arranged key exactly once. Asrabkin (talk) 22:03, 8 October 2009 (UTC)

Quantum Cryptography vs QKD

(moved from TODO list)

This page should really be called "Quantum Key Distribution" NOT "quantum cryptography" since the latter refers to a much wider range of tasks (e.g. Quantum bit commitment) —Preceding unsigned comment added by 192.33.98.48 (talk) 26 January 2019 (UTC)

I think this has been mentioned before, and the "quantum key distribution" page does redirect to here. However as there's very few non-qkd quantum cryptography pages (there is no quanutm bit commitment page for example) on wikipedia, a general quantum crytography page would probably just link to this page currently. If anyone can find enough non-qkd pages to make a quantum cryptography article viable, this page could be moved to "quantum key distribution". We'd have to make sure we avoid confusion though, as almost everyone looking up "quantum cryptography" is looking for information on qkd, and probably arn't aware of the technical difference. centie (talk) 13:13, 23 March 2010 (UTC)

NO, i think the name of this page is correct, because mainly quantum cryptography consist in distribution of the key in a secure proofed way, then after key distribution classical cryptographic system (one time pad) are used to exchange messages. I have many references articles about this and i am surprised that any one of them is not in this page. -Undestading Quantum cryptography - idquantique -Talking on quantum cryptography- Samuel J.Lomonaco -Experimental Quatum cryptography- Bennet, Bessete, Brassard (actually i am studing quatum authentication)