Cryptography Stack Exchange
Cryptography Stack Exchange

Questions tagged [quantum-cryptography]

Quantum cryptography describes the use of quantum mechanical effects to perform cryptographic tasks. This is not to be confused with quantum computing or cryptanalysis techniques such as Shor's algorithm.

Quantum cryptography describes the use of quantum mechanical effects to perform cryptographic tasks, this method is alternatively known as quantum communication. These terms are interchangeable in most literature. This is not to be confused with quantum computing or cryptanalysis techniques such as Shor's algorithm.

Quantum Privacy Amplification (often called Quantum Key Distribution) is a sub-topic of Quantum Cryptography.

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New quantum attack on lattices (or Shor strikes again)?

Lior Eldar and Peter W. Shor published a paper on arXiv.org in which they present a new quantum algorithm against a variant of BDD. They claim that their new algorithm can efficiently solve the following problem: Given a lattice $L$, a vector $v$,…
mephisto
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How effective is quantum computing against elliptic curve cryptography?

I've been reading the Wikipedia page on Elliptic-Curve Cryptography and I came across the following. in August 2015, the NSA announced that it plans to replace Suite B with a new cipher suite due to concerns about quantum computing attacks on ECC.…
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What does the work "An Efficient Quantum Algorithm for Lattice Problems Achieving Subexponential Approximation Factor" mean?

In An Efficient Quantum Algorithm for Lattice Problems Achieving Subexponential Approximation Factor, the author claims they give a polynomial-time quantum algorithm for solving the Bounded Distance Decoding problem with a subexponential…
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In layman's terms, how does Shor's algorithm work?

I've just been reading up on Shor's algorithm, and I find it both fascinating and baffling. I don't understand much about it, other than that it can factor semiprimes in polynomial time. Could someone explain how it works in layman's terms and why…
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Will IBM's Condor quantum processor run Shor's Algorithm to crack a 256-bit Elliptic Curve key?

Yesterday IBM announced that they have a 433 bit quantum computer, called Osprey. There is nothing in the press releases I can find that says whether it can or cannot run Shor's Algorithm. They also say they are on track to release "Condor", an 1121…
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What does a "real" quantum computer need for cryptanalysis and/or cryptographic attack purposes?

The cryptographic world has been buzzing the word "quantum" for a while now (even the NSA is currently preparing itself for a post-quantum crypto world) and quantum-related hardware engineering is evolving constantly. For example: the 5-qubit…
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What is the difference between Shor's algorithm for factoring and Shor's algorithm for logarithms?

There is a paper from Peter W. Shor from 1994: Algorithms for Quantum Computation: Discrete Logarithms and Factoring, and I have a question about it and the algorithms presented. For integer factoring problem, Shor's algorithm works as a fast…
osgx
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Dice vs quantum random number generator

I recently championed quantum key distribution networks. This has led me to also question quantum random number generators. It appears that randomness is randomness, even if made by custom quantum hardware featuring lasers and photon genies. It…
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Can Shor's algorithm compromise RSA when both the public and private key are secret?

If RSA is to create a public-private key pair and encryption is performed on plain test P to create ciphertext C, given P and C could Shor's algorithm be used to find either of the public and private keys? You have both the plain text and cipher…
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Qubit / Qutrit - Is there a theoretical limit on how many orthogonal states a quantum bit has?

Seems like a quantum bit with $3$ orthogonal quantum states is called a qutrit - and they have been demonstrated practically. In comparison with $n$ qubits that have ~$2^{n}$ states, these have ~$3^{n}$ states. Is there a theoretical upper-limit on…
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Is full Homomorphic encryption quantum resistant?

Since most of our asymmetric encryption algorithms are going to be out-of-date in a couple of year due to Shor's algorithm, I was wondering about the future of FHE schemes. I have found this paper, which states: "It is impossible to construct…
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Are there any applications of Quantum Computation to Cryptography? (besides Cryptanalysis)

I know that people may be yelling "of course!" at the title of the question, but my concern is not about how to construct quantum-resistant primitives, but rather how to use the power of quantum computers to develop secure and efficient…
Daniel
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What role plays Quantum Fourier Transformation in Shor's integer factorization algorithm?

I cannot seem to understand the role or goal of Quantum Fourier Transformation in Shor's integer factorization algorithm. Is it used to collapse all quantum states into one, in which it has a factor of a given input $n$?
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Can we break RSA with an optical Fourier transform?

We all know that RSA can be compromised using Shor's quantum algorithm. The horsepower underlying this algorithm is the Fourier transform. However, we can use alternatives to perform this function, such as an optical Fourier transform coprocessor…
shumy
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How can Shor's Algorithm be applied to ECC?

I have not found a specific answer to this question on here. Shor's algorithm can be used to factorize a large (semi)prime $N$ by reducing the task to period-finding of a function $f(x)=x^a$ mod $N$. This is done by creating an equal superposition…
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