For questions about quantum key distribution (QKD), a secure communication method that implements a cryptographic protocol using quantum mechanics.
Questions tagged [qkd]
76 questions
22
votes
3 answers
Advantage of quantum key distribution over post-quantum cryptography
Post-quantum cryptography like lattice-based cryptography is designed to be secure even if quantum computers are available. It resembles currently employed encryptions, but is based on problems which are most likely not efficiently solvable by a…
M. Stern
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14
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2 answers
Why is the efficiency of Ekert 91 Protocol 25%?
In Cabello's paper Quantum key distribution without alternative measurements, the author said "the number of useful random bits shared by Alice and Bob by transmitted qubit, before checking for eavesdropping, is 0.5 bits by transmitted qubit, both…
Lynn
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10
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1 answer
What authentication protocol to use for BB84 and other QKD protocols?
Just like other classical and quantum key distribution protocols, BB84 is vulnerable to "man"-in-the-middle attacks, where Eve pretends to be Bob to Alice, and Eve pretends to be Alice to Bob. The countermeasure against this potential…
Bruno Rijsman
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7
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1 answer
What role do Hecke operators and ideal classes perform in “Quantum Money from Modular Forms?”
Cross-posted on MO
The original ideas from the 70's/80's - that begat the [BB84] quantum key distribution - concerned quantum money that is unforgeable by virtue of the no-cloning theorem. A limitation was that the quantum money required the bank…
Mark Spinelli
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6
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2 answers
Non maximally entangled states for QKD
Why aren't non maximally entangled states produced and used in quantum key distribution schemes? What would be the advantage/disadvantage to use such states rather than maximally entangled ones?
Sujan Vijayaraj
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6
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3 answers
In what ways can qubits be used for applications that do not require entanglement?
Many good questions on this site have explored how entanglement lies at the boundary between the quantum world and the classical. For example in computational speedups, or teleportation or superdense coding, at least two qubits are entangled in some…
Mark Spinelli
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6
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1 answer
Lattice based cryptography vs BB84
Am I correct in thinking that post-quantum cryptography such as lattice-based solutions run on classical computers are resistant to quantum attacks (as opposed to RMS), whereas quantum key distribution schemes such as the BB84 are designed to run on…
Matthew Giles
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5
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Average secret key rate calculation
I am working on a problem related to average secret key rate calculation in satellite quantum key distribution (QKD). The problem is similar to a paper on arXiv:1712.09722 (P. No. 21).
In a single mode transfer version of entanglement based QKD, we…
Shikhar Arora
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5
votes
1 answer
In the BB84 protocol, for what error thresholds can Alice and Bob not establish secure bits?
Suppose Alice and Bob can communicate over a quantum channel. The quantum channel is noiseless in the absence of eavesdropping, a condition that cannot be guaranteed. They can also communicate over a classical channel which may be tapped, but not…
Condo
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4
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Is there a BB84 "man"-in-the-middle attack forcing the same keys on Alice and Bob known to Eve
Consider the following scenario:
Alice and Bob run BB84 to each other.
Eavesdropper Eve is present in the middle. Here we assume that she has access to all channels: the quantum channel, in the classical control channel (where the BB84 protocol…
Bruno Rijsman
- 353
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4
votes
2 answers
What is the difference between CV QKD and DV QKD?
I know what QKD is, as a concept but I recently found papers mentioning continuous-variable quantum key distribution , and discrete-variable quantum key distribution . So I would like to know what is the difference between them?
Also, when we…
user206904
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3
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1 answer
Counting channel uses of the lossy bosonic channel or definition of channel uses
The PLOB-bound ("Fundamental Limits of Repeaterless Quantum Communications") gives an asymptotic upper bound on the secret-key rate per used lossy bosonic channel.
However, I'm not sure how to count the number of used channels in a physical…
user1677907
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3
votes
1 answer
Inconsistent values of $S$ (CHSH inequality) in my Qiskit implementation of the E91 protocol
I'm currently experimenting with Qiskit and I wanted to implement the Ekert's E91 protocol. I had no problem writing the code, but then I got to the point of calculating the $S$ value to detect the presence of an eavesdropper. In all the papers…
Lorenzo
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3
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1 answer
BB84 cloning games and state splitting
I have been trying to simulate cloning games for BB84 states with qiskit.
The game I am struggling with is as follows, where Alice plays against Bob and Charlie.
Alice creates a state $H^{\theta}|x \rangle $, with $x, \theta \in \{0, 1\}$.
Alice…
Lorenzo Senarigo
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3
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1 answer
DOS attacks on QKD Systesm
In the BB84 QKD or similar protocol, we know that eavesdropping or interception during secret key generation can be detected, prompting both parties to discard the transaction and attempt a new one. However, what if, as a hacker, my goal is to…
Azad Prajapat
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