Skip to main content
New
Stack Overflow Jobs powered by Indeed: A job site that puts thousands of tech jobs at your fingertips (U.S. only). Search jobs

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.

Filter by
Sorted by
Tagged with
2 votes
1 answer
82 views

Quantum many time pad

In the Quantum One Time Pad, an $n$-qubit quantum state can be perfectly encrypted (as in the classical OTP) using $2n$ classical bits. In the classical OTP, I'm allowed to send many times the ...
manta's user avatar
  • 87
3 votes
1 answer
108 views

Hybrid argument for quantum states

The usual hybrid argument tells us that if two efficiently sampled ensembles are computationally indistinguishable based on a single sample, then, computational indistinguishability holds even for ...
manta's user avatar
  • 87
0 votes
0 answers
100 views

Kyber and Dilithium usage limits?

What are the theoretical usage limits of Kyber and Dilithium? Are there any sources to back this up? Maximum number of encryptions/signatures allowed per key, etc.?
Joe's user avatar
  • 73
1 vote
1 answer
81 views

Tensor product of Pseudorandom States

I am reading the paper Pseudorandom Quantum States,where the following candidate was shown to be a Pseudorandom state, called the complex random phase state: $\mathrm{PRF}_k:X → X$ be a keyed ...
bluebird's user avatar
2 votes
0 answers
88 views

Poly-commitment based on Bulletproofs

I am reviewing the ZKP course, represented by the university of Berkley (https://zk-learning.org/). In pages 41 and 42 of lecture 6 that is attached below (https://zk-learning.org/assets/lecture6.pdf),...
tesoke's user avatar
  • 181
3 votes
1 answer
88 views

Where does the 8 come from? Generic Search Problem with Bounded Probabilities

I am working with lossy ID-schemes and their security in the QROM. Following the article of Kiltz et al. , I am at a loss of the number 8 appearing in most reductions throughout the article. I know it ...
Rory's user avatar
  • 335
2 votes
1 answer
525 views

Is pairing-based crypto post-quantum secure?

Bilinear Pairings are widely used in many new schemes like Group Signature and Aggregate Signature. The problem is whether it is post-quantum secure. In other words, does Bilinear Diffie-Hellman ...
Chunchi Liu's user avatar
2 votes
0 answers
39 views

Proving the minimal entropy of Dilithium-QROM?

I am working with the securit yof CRYSTAL's Dilithium signature in the QROM. I am working with Kiltz et al.'s approach through lossy ID-schemes and looking at the proof of minimal entropy for the $DFS[...
Rory's user avatar
  • 335
5 votes
1 answer
153 views

Quantum computationally indistinguishable

We say two states $\sigma, \rho$ are computationally indistinguishable, if for efficient quantum algorithm $\mathbf{A}$, $|P(\mathbf{A}(\rho)=1)-P(\mathbf{A}(\sigma)=1)|$ is negligible. I want to show ...
bluebird's user avatar
5 votes
1 answer
488 views

Do we need the quantum random oracle model (QROM)?

I am currently studying the proof of the Dilithium signature in the quantum random oracle model (QROM). I am curious to hear if anyone have any thoughts on the importance of having proofs in the QROM ...
Rory's user avatar
  • 335
3 votes
1 answer
860 views

CRYSTALS-Dilithium - How do the supporting algorithms work?

I am studying the Dilithium signature from Ducas et al's CRYSTALS-Dilithium: A Lattice-Based Digital Signature Scheme. Wanting to understand how the supporting algorithms work together, I am trying ...
Rory's user avatar
  • 335
1 vote
1 answer
76 views

LWE encryption: Errors for encrypted messages

I am following this paper Encryption from Learning with Errors for the generation of errors e1 and e2 to retrieve the ciphertext u and v as described below. ...
user108142's user avatar
2 votes
1 answer
152 views

Sending photons in Quantum Cryptography

Bob has two detectors + and x. You can see it in the picture I sent. Alice sends a photon with vertical polarization and Bob uses the + detector and the detector is detecting Alice's photon. Bob's + ...
Tatsuya's user avatar
  • 21
0 votes
1 answer
99 views

Unable to retrieve the binary string using LWE and Lattice-based decryption

I am new to this encryption scheme, so I may not be exactly sure of its implementation. I have a list of (u, v) ciphertext pairs to decrypt, each of them are 1-bit. ...
user108142's user avatar
1 vote
2 answers
156 views

LWE and Lattice-based cryptography: How to recover binary message $M$ from $(u, v)$ values?

I am given a set of $(u, v)$ values, matrix $A$, primary key vector, private key vector, error vector and prime $q$. I wanted to recover the binary value of each $(u, v)$ pairs using LWE decryption. ...
user108142's user avatar
1 vote
2 answers
215 views

Are lattice-based cryptography and error-correcting codes mathematically unsound?

From Ronald de Wolf's The potential impact of quantum computers on society: The first is so-called post-quantum cryptography. This is classical cryptography, based on computational problems that are ...
HarryFoster1812's user avatar
1 vote
3 answers
180 views

Why can't we just increase the bit length to counteract shor's algorithm?

I know that it sounds like a very stupid question but if Shor's algorithm has a complexity of roughly $n^3$ why cant we just increase the bit size until the time for the algorithm to run is ...
HarryFoster1812's user avatar
4 votes
2 answers
231 views

Does Quantum Key Distribution (aka: QKD) qualify as "Cryptography"?

This may be a polemic question, but since I did read the rules of the site and "terms and definitions" appear to be legitimate subjects, I want to raise this because I find this interesting, ...
Amit's user avatar
  • 432
0 votes
1 answer
48 views

What is the best method to compose a set of matrices into one and then unambiguously decrypt it?

I am presented with the following problem: Given a set of matrices $M = \{A^i_{m,n} : 0 < i < 101 \}$ design a procedure to compose all of them into one encrypted matrix $E_{m,n}$ and later ...
max's user avatar
  • 219
4 votes
2 answers
954 views

How could ECDSA be broken with prime factorization through Shor's Algorithm?

could anyone help me understand how is ECDSA broken using Shor's Algorithm? All the papers I find are too complex to understand, and even though I feel I understand some concepts, some others are a ...
Pau T's user avatar
  • 61
19 votes
1 answer
5k views

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 ...
Simon G.'s user avatar
  • 343
1 vote
1 answer
99 views

Could Grover's algorithm perform a search in N/2 for a match in a particular subset of a hash function preimage?

Suppose I first define some function f(x) where x is some unsigned 256-bit integer, and the function's output is a set of distinct strings of any length so that output set would be 2^256 unique ...
bca-0353f40e's user avatar
1 vote
1 answer
136 views

value bound of r⋅e for LWE Decryption correctness

For LWE decryption, Someone told me that If we can bound r⋅e by q/4 then we can retrieve M by checking if this is closer to <...
kevin's user avatar
  • 121
1 vote
1 answer
344 views

Encryption and decryption for LWE

For https://asecuritysite.com/public/lwe_ring.pdf#page=9 , could anyone explain how the encryption and decryption for LWE work ? When I do more reading on https://summerschool-croatia.cs.ru.nl/2015/...
kevin's user avatar
  • 121
3 votes
1 answer
488 views

Simon's quantum algorithm for symmetric encryption

Though there are many papers available on application of Simon's algorithm for symmetric encryption, nothing is clear on implementation - like how to build the oracle, how many PT-CT combinations are ...
Kathiresan's user avatar
1 vote
1 answer
897 views

Why are zk-STARK quantum secure?

I have a rough idea of how STARK work, but I want to know which part makes them quantum secure. Is it because when the prover generates the proof they use the random number from the Merkle root, which ...
Fieldza555's user avatar
2 votes
3 answers
241 views

Two untrusting people want to come up with a random number

Two people want to come up with a random number. They don't trust each other nor any third party. What are the known solutions to this problem? I am a quantum cryptography student and am currently ...
Dotman's user avatar
  • 121
1 vote
1 answer
84 views

Asymmetric key Cryptography

In asymmetric key cryptography, public key is available to everyone. If an attacker encrypts the message sent by another user then the receiver might receive that message. Then how the security is ...
Ruhan Saini's user avatar
2 votes
0 answers
162 views

What is the fundamental difference between quantum secure direct communication (QSDC) and quantum key distribution (QKD)?

Can one be thought to be a more powerful resource than the other? It seems to me like you could use QSDC to achieve the same thing as QKD (sharing of a secret key) without the use of a classical ...
Qubed's user avatar
  • 56
4 votes
2 answers
314 views

Testing of PQC NIST round3 submissions

I am new to this field and have some concerns regarding PQC; How does NIST do a comparison that a particular algorithm is efficient and its security can not be broken by future quantum attacks? I am ...
Abdul Muneeb's user avatar
0 votes
1 answer
96 views

QKD measuring qubit with wrong bases

I'm trying to end the research work for my master thesis about BB84 QKD (and QBC) and a basic problem of quantum mechanics is blocking me. I'm trying to do a probability calculus of the action of ...
VitoShade's user avatar
4 votes
1 answer
171 views

A question about performing quantum computations on uniform superpositions

Let us consider the following situation. Let $U_f$ be a gate computing $f$ mapping $\{0,1\}^n$ to $\{0,1\}^n$. That is, $U_f\left\vert x,0^n\right\rangle=\left\vert x,f(x)\right\rangle$. Let $\left\...
Henry's user avatar
  • 55
5 votes
1 answer
186 views

What are the misconceptions of IBM's CEO Arvind Krishna talk on the "Axios on HBO" about the quantum computing

IBM CEO Arvind made a talk in HBO's Axios program. It seems that there are misconceptions/misleading/flaws in reasoning etc. What are those! Some of the details of the speech is given as; IBM says ...
kelalaka's user avatar
  • 48.8k
25 votes
3 answers
6k views

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 ...
user77340's user avatar
  • 797
4 votes
1 answer
1k views

In quantum cryptography, why can a qubit can be both 0 and 1 at the same?

The texts below are from some tutorial, and it says (in bold format below) a qubit can be both 0 and 1 at the same time. It sounds very strange to me, can you please explain why? Quantum cryptography ...
common2k's user avatar
0 votes
1 answer
101 views

Density operator

How I calculate density operator for pure quantum state for bb84 in 2D? BB84 protocol, proposed in 1984 by Bennett and Brassard – that's where the name comes from. The idea is to encode every bit of ...
Rasha rashed's user avatar
6 votes
2 answers
193 views

Why doesn't this factoring to order-finding reduction work?

Scott Aaronson likes to motivate the factoring-to-period-finding algorithm used inside Shor's algorithm as follows. Now, I want you to step back and think about what this means. It means that, if we ...
panto's user avatar
  • 63
2 votes
0 answers
70 views

What are some "must-read" papers for someone getting into Quantum Cryptography? [closed]

I'm a graduate student that just finished a first course on quantum computation. I've also done a graduate-level course in (classical) cryptography. I'm interested in Quantum Cryptography and would ...
CSSTUDENT's user avatar
  • 121
1 vote
0 answers
68 views

How to prove that the given encryption scheme have ciphertext indistinguishability for all PPT adversaries?

I am not sure how to prove that the given two scheme is perfectly indistinguishable for all PPT adversaries!
Student forlife's user avatar
0 votes
0 answers
149 views

Can quantum computers solve NP-Complete problems?

As far as I know, quantum computers are able to solve only some of the NP-Problems in polynomial time, using the Grovers algorithm. I read that if one manages to create a reduction of Grovers ...
namaewa's user avatar
  • 59
0 votes
1 answer
118 views

Soundness of Trevisan’s Extractor Against Quantum Side Information

I wonder how sound Trevisan's extractor can be against quantum side information. I checked many papers. And all of these papers were aiming to explain how sound Trevisan's Extractor is against quantum ...
quest's user avatar
  • 151
0 votes
0 answers
170 views

Quantum key distribution using BB84 protocol

Quantum key distribution using BB84 protocol. The Secure key rate $R$, is given by $$ \quad R=1 - 2h(e_b) \tag{1}\label{q1}$$ where $e_b$ is the quantum bit error rate (QBER), $h(x)$ is the Shannon ...
Rasha rashed's user avatar
2 votes
1 answer
142 views

Differences between Extractors and Privacy Amplification for Quantum Random Generators

We know that for the last step of QRNG: we need to separate quantum and classical noises from each other so we use extractors, after extractor we need privacy amplification step. At this point: if ...
quest's user avatar
  • 21
0 votes
1 answer
620 views

Which QKD schemes don’t utilize an authenticated classical channel?

This Wikipedia article discusses one drawback of quantum key-distribution: The main drawback of Quantum Key Distribution is that it usually relies on having an authenticated classical channel of ...
Keshav Srinivasan's user avatar
1 vote
0 answers
56 views

Spontaneous parametric down-conversion [closed]

we generate heralded single pho- tons via spontaneous parametric downconversion using a 5 mm long periodically-poled potassium titanyl phosphate (ppKTP) crystal pumped with a 405 nm diode laser (200 ...
Rasha rashed's user avatar
1 vote
0 answers
91 views

XOR & AND equation in quantum computing ... is it correct?

I'm trying to understand the following equality found in a paper of quantum key distribution Fully device independent quantum key distribution : $$a \oplus b = x \wedge y$$ As far as I know; $\oplus$ ...
terence's user avatar
  • 21
1 vote
0 answers
70 views

The existing approaches based on machine learning for cryptography [closed]

i'm working on a paper about Machine learning and Deep Learning and i'm wondring about the uses of this domain in cryptography!! so what are these application of Ml that we use in cryptography and the ...
Aicha Zerouali's user avatar
2 votes
1 answer
226 views

Is there a notion of "computational security" in quantum cryptography?

In classical cryptography, security proofs are often based on the (assumed) computational hardness of some mathematical problem. Using the principles of quantum mechanics might provide means to design ...
jgerrit's user avatar
  • 51
3 votes
1 answer
179 views

Quantum-secure obfuscation

My question is a follow-up to a recent question regarding quantum-secure time-lock puzzles (TLPs). TLPs can be built (in principle) from indistinguishability obfuscation (iO) [BGJ+,BGL+] as noted in ...
ckamath's user avatar
  • 5,268
1 vote
1 answer
160 views

Implications of Shor's algorithm on $F_{2^m}$ elliptic curves and GHASH

The security of elliptic curves depends on the difficulty of the discrete logarithm problem. Should Shor's Algorithm ever prove viable then elliptic curves would cease to offer any useful security ...
neubert's user avatar
  • 2,937