Questions tagged [quantum-computing]
A computation model which relies on quantum-mechanic phenomena, such as entanglement and superposition. This generalizes the probabilistic model of computation.
43
questions
20
votes
1
answer
5k
views
How does IBM's 53-bit quantum computer compare to classical ones for cryptanalytic tasks?
IBM just announced "a new 53-qubit quantum computer".
How does it compare to classical computers, performance-wise, for cryptanalytic tasks? E.g. finding a 48- or 64-bit value whose SHA-256 has a ...
- 143k
17
votes
0
answers
426
views
Fewest qubits required for the discrete logarithm problem and integer factorization
According to a paper from 2002, the most efficient circuit to factor an $n$-bit integer requires $2n+3$ qubits and $O(n^{3}\lg(n))$ elementary quantum gates, assuming ideal qubits. Later on, according ...
- 15.4k
16
votes
2
answers
4k
views
New paper claims quantum polylog time attack on AES
It is well known that Grover's algorithm can solve AES in $O(\sqrt{n})$ time, which is why symmetric key length needs to be double to maintain their security level in the face of a quantum adversary. ...
- 1,365
15
votes
3
answers
7k
views
Can or can not D-Wave's quantum computers use Shor's and Grover's Algorithm to find encryption keys? Why?
I read that a company called D-Wave Systems has and is manufacturing quantum computers of 128 qubits.
Can they or can they not use Shor's and Grover's algorithms for finding RSA-keys? If they can't ...
- 183
11
votes
4
answers
8k
views
How will the world learn that Q-Day has arrived?
I wonder how the world will come to know that scalable, fully fault-tolerant quantum computers capable of running Shor's algorithm have arrived. The day when this happens has been referred to as "...
- 289
11
votes
2
answers
3k
views
Can quantum computers put computer security in jeopardy?
There are many articles about quantum computers describing how powerful they are in computing and that they can solve very complicated equations in a short time.
One of the biggest security measures ...
- 1,960
6
votes
3
answers
9k
views
Can Quantum Computers crack RSA and AES?
Im trying to learn more about cryptography and ran into a post, Is AES-128 quantum safe?, which asks if AES-128 is safe. From the articles and replies it seems that AES-128 (symmetric key) is safe ...
6
votes
1
answer
1k
views
How many qubits can break NIST P-521 ECC?
NIST P-521 has the longest key size for standardised ECC, which has 521 bits instead of 512. If a quantum computer is available, how many qubits can break P-521?
- 361
5
votes
1
answer
2k
views
Factoring 2048-bit integer with quantum computer?
In this paper, there is a statement in the abstract:
Our construction uses $3n + 0.002n \log(n)$ logical qubits, $0.3n^3 + 0.0005n ^3\log(n)$ Toffolis, and $500n^2 +n^2 \log(n)$ measurement depth to ...
- 640
5
votes
1
answer
187
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 ...
- 49.1k
4
votes
1
answer
2k
views
Is Mega.nz encryption vulnerable to brute force cracking by quantum computers?
I am interested in Mega.nz cloud storage.
It is using end-to-end encryption.
It says that it uses AES-128 to encrypt files
And there are more details in their white paper
But I saw that quantum ...
- 43
4
votes
1
answer
172
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\...
- 55
4
votes
1
answer
139
views
Difficulty of Shor's algorithm in a Schnorr group as a function of the modulus
Consider a Schnorr group with order a prime $q$ sized for security against current computers (like $q$ of 256 bit); modulus a prime $p=q\,r+1$ large enough (e.g. 3072 to 32768-bit) that the algorithms ...
- 143k
4
votes
0
answers
77
views
Comparing quantum computing resources to break the DLP on elliptic curve group vs Schnorr group
Take an elliptic curve group of 256-bit prime order $n$ over a 256-bit prime field in which the Discrete Logarithm Problem is believed hard, e.g. secp256r1. Build an isomorphic Schnorr group by taking ...
- 143k
4
votes
0
answers
142
views
Are Memory-Hard Functions de-facto quantum resistant?
Searches have returned absolutely no results on this question. With that in mind, I assume the answer is either painfully obvious ('of course quantum computers get no advantage when it comes to ...
- 141