Questions tagged [attack]
A cryptographic attack tries to theoretically and/or practically attack the security properties of a cipher and/or algorithm.
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How to prove that a rainbow table is complete?
Passwords that are hashed but not salted can be cracked using the rainbow table. I went through this and this which explains the logic behind rainbow table very well.
But I am missing something about ...
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Short padding + known prefix RSA attack
Suppose I have a message in the form of:
$m = \text{prefix} \mathbin\| \text{secret} \mathbin\| \text{padding}$
We have:
$e=3$
$n$
$n_\text{padding}$ (length of the random padding, <$1/4$ of $m$)...
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Attacks on LWE when q is a power of 2
I am working on an LWE instance where q is a power of 2 and I'm wondering if there is any literature about attacks in this context, especially if there are any attacks which work significantly better. ...
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Encrypt N plaintexts which have the same first 3 bytes using DES [closed]
I would like to have the answer to this problem that my professor gave me, I'm not sure about that. The problem is: "Consider a system where DES is used to encrypt simple and short HTTP requests ...
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Is there a problem with this specific RSA protocol?
So a protocol uses two random primes $P$ and $Q$ with the equivalent bit length of around 2048 bits, multiplies to form $N$. The encryption function in detail is:
$m^e \bmod\ N$
$(\text{512-bit-random-...
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How to attack Oblivious Transfer from a malicious sender that can deviate from the protocol
I am looking at at the $1–2 \space \text{oblivious transfer}$ that is described here: https://en.wikipedia.org/wiki/Oblivious_transfer#:~:text=In%20cryptography%2C%20an%20oblivious%20transfer,Rabin.
I ...
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Complete crypto attack explanation or hierarchy including statistical attack, entropy attack, correlation attack, differential attack?
How exactly statistical attack(resistancy tested using histogram analysis), entropy attack(resistancy tested using entropy information), correlation attack(resistancy tested using correlation ...
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Known attacks against ECC in case many multiples are known?
Suppose there's a secret value x, an elliptic curve with the (public) generator G, and a sequence of secret values ...
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Can I alter encrypted data without decrypting it?
I didn't find a direct solution for it. Can I modify encrypted data without accessing it?
If there is an example, I would appreciate it.
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Difference between eavesdropping and traffic analysis
I was wondering what is the conceptual difference between these two passive attacks on a network. I was reading about them on Wikipedia and they seem quite similar to me. Is there a difference?
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AES 5 and 6 round SQUARE Attack
SQUARE attack on AES128 requires a single delta set for 4-round variant, or I assume single delta set is enough since keyspace is reduced to few keys which can be easily brute-forced. However, as we ...
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Is there a term for cryptographic attacks where you can verify decryption without assuming any known structure on the plaintext?
The questions https://security.stackexchange.com/questions/1696/if-someone-breaks-encryption-how-do-they-know-theyre-successful and https://security.stackexchange.com/questions/119887/how-to-know-if-a-...
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On the current memory retain limits for the coldboot attack (2020)
ColdBoot attack is introduced by Halderman et. al in 2009
Lest we remember: cold-boot attacks on encryption keys
In their articles, they represent experimented that
We found that the dimensions of ...
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What are the current known weaknesses/attacks on quantum key distribution?
I am writing a paper on the implementation of QKD in the future. I want to know if there are any viable attacks on the BB84 protocol or QKD in general? I know of the Photon Number Splitting attack or ...
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Are there any mutual-distance bounding protocols in RFID context?
Distance-bounding algorithms are a classical solution for the Relay Attack, wherein a verifier can determine an upper bound on its distance from the prover.
However, recent literature is discussing ...
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Boomerang attack - looking for simply explanation
Can someone explain to me in a simple way how it works?
I know what differential cryptoanalysis is, but my knowledge is rather amateur. Nevertheless, reading the post on Wikipedia:Boomerang Attack I ...
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1answer
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Is it possible to acquire the next keystream of Salsa20? (If you know part of the keystream)
When you know the Salsa20's keystream, how do you know the next keystream?
In other words, can I infer the next keystream when I don't know the Key and IV of Salsa20, but the keystream is ...
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Adversary for attack on one variant of ElGamal
I came by the following question:
Consider the following variant of ElGamal encryption. Let $p= 2q+ 1$,
let $G$ be the group of squares modulo $p$ so $G$ is a subgroup of
$Z_p^*$ of order $q$, and ...
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Proof by reduction for for digital signature scheme $S_2((sk_0,sk_1), m):=(S(sk_0,m), S(sk_1,m))$
Let $(Gen,S,V)$ be a secure signature scheme (existentially unforgeable under a chosen message attack) with message space${\{0,1\}}^n$. Generate two signing/verification key ...
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Which RSA keys are actually attacked In practice?
I understand that it is important to check how hard it is to attack RSA keys, but I assume at some key size attackers would not even try. Real attacks are carried out by exploiting mistakes in the ...
Gilles 'SO- stop being evil'
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Security of a custom AES-based attack model
Provided that:
$AES(plaintext, key)$ is the standard AES block cipher for a 128 bits block.
$\oplus$ is the standard XOR operation.
$K$ is a constant 128 bits pseudorandom value, which is used as the ...
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May an adversary be fooled by a random-looking input that in reality is fixed?
I want to prove the EUF-CMA-security of a signature scheme. It is a variation on an established scheme, therefore I would ideally like to reduce the new-scheme-security to the old-scheme-security.
the ...
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When attacking keyed algorithms, how is it known when the output is correct?
I've been reading a little bit about cryptanalysis, and I'm wondering how attacking algorithms that work on keys is performed.
It's obvious how algorithms like MD5 are attacked, in pseudocode:
...
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The aftermath and considerations of the new record of 30750-Bit Binary Field Discrete Logarithm - 2020
Granger et al. recently published a paper about breaking a record for discrete logarithm on the Binary field
Computation of a 30 750-Bit Binary Field Discrete Logarithm, Robert Granger and Thorsten ...
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Cracking RSA with small plaintext
I read a CTF writeup about cracking 4 primes RSA numbers from here:
Given $p, q, r,$ and $p+q+r$ are prime numbers.
The challenge encrypts the flag with a modulus $N=(p∗q∗r)∗(p+q+r)$
and gives the ...
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1answer
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Iterations of pollards kangaroo attack on elliptic curves
I want to understand the Pollard kangaroo attack on elliptic curves. I found this Pollard's kangaroo attack on Elliptic Curve Groups Q/A pretty helpful, but not complete. The posts provides a pretty ...
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Code implementation of NTRU lattice attack
As mentioned here, BKZ is one way to break the NTRU lattice What is the most efficient attack on NTRU?
I was wondering if there are any source codes which actually implemented this on the weaker NTRU ...
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What is the ChainOfFools/CurveBall Attack on ECDSA on Windows 10 CryptoAPI
What is the ChainOfFools/CurveBall Attack on ECDSA on Windows 10 CryptoAPI (Crypt32.dll)
Could someone provide details?
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Understanding birthday attacks on 256 bit hashing and 512 bit hashing [duplicate]
Does it make a difference against birthday attacks if the algorithm that I am using is 512 bit hashing?
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Check linear and differential cryptanalysis of a new block cipher [duplicate]
I am developing a new block cipher primitive. I would like to test its robustness against attacks of linear and differential cryptanalysis. Is there a tool to evaluate this using only plaintext and ...
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MOV-attack on ecc: Time complexity and example
There already is this pretty big post about the MOV-attack. It states, that the discrete logarithm problem on elliptic curves can be transformed to a discrete logarithm problem over a finite field. ...
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Pollard Rho Optimization
One of the most important attacks on Elliptic Curve cryptography is Pollard's Rho method. The effect on security can be seen on SafeCurves.
This attack is pretty old and there has been a bunch of ...
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Curve25519 Attacks and Security
Curve25519 is a pretty secure way to exchange a key. In the original Paper and on SafeCurves a lot of attacks and security aspects are mentioned:
Attacks:
Brute force: This one is theoretically ...
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312 views
Pohlig Hellman and small subgroup attacks
While studying Curve25519 I read about the small subgroup attack in chapter 3. So far i know, that you need a point with a small subgroup to do such an attack. Curve25519 has a basepoint with prime ...
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Which cryptographic attacks can AES 128-bit withstand?
Most of the articles and forums are stating that the Brute Force attack can test the strength of an encryption algorithm. However, I am looking for those attacks that AES can withstand for the testing ...
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How to solve high exponent attack for same message in RSA
I know Håstad's broadcast attack when e = 3, but what if e = getPrime(randint(350))?
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XOR cipher with fixed key and known relation among plaintexts
I have three messages, each known to be XOR-encoded, with the same key used for each message of this XOR cipher.
Encoded message 1: $e_1\,=\,00100111010$
Encoded message 2: $e_2\,=\,01001110110$
...
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Can we defends against RSA Timing attack when we use java.math.BigInteger.modPow?
I think that Montgomery and sliding window techniques are applied within java.math.BigInteger.modPow (and more specifically ...
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Attack against $\operatorname{DESA}_{k,k_1} (x) \underset{\text{def}}= \operatorname{DES}_k(x)⊕k_1$
Problem 5.16 in this pdf, from the book: Christof Paar, Jan Pelzl, Understanding Cryptography
5.16. This is your chance to break a cryptosystem. As we know by now, cryptography is a tricky business. ...
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Which attacks are possible against raw/textbook NTRU encryption?
In the same fashion that these questions about attacks to textbook RSA and ECC, I was wondering what are the immediate drawbacks of applying NTRU Encryption directly, without any padding scheme, such ...
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Why are the indicator drums of a Bombe machine labelled from A to Z clockwise?
I am researching the Bombe Machine, having just completed a project on the Enigma Machine. I visited The Rutherford Journal - The Turing Bombe, and it claimed that
The scales on the three ...
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475 views
Why does the Bombe not consider the Ringstellung when determining stecker pairs?
I am doing research on the Bombe Machine, and I read that when the Bombe tries to find the stecker (plugboard) partners of letters, it only needs to use the rotor types and arrangement and also the "...
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Does having a hash of a password jeopardize the security of plaintext that was encrypted with that password?
A malicious actor wants to decrypt ciphertext that was encrypted with a password. He also possesses the hash (bcrypt/PBKDF2) of that password. Does he have any significant practical advantage in ...
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Is Joux's multicollision attack applicable for truncated SHA256?
Joux presents an elegant way to generate k-way multi-collisions with about as much effort as generating a single collision: https://www.iacr.org/archive/crypto2004/31520306/multicollisions.pdf
...
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Secret sharing scheme WITHOUT Shamir Secrete Sharing
I am planning to use the following XOR scheme to divide a secret into only 2 shares (I do not want to use Shamir Secret Sharing for different reasons that are beyond the scope of this post).
Here's ...
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Can MFA codes be predicted if you know what their values were at a previous time?
I use an app on my phone that, after scanning a QR code on a website, gives me 6-digit codes which change every 30 seconds. These codes can be used for Multi-Factor Authentication (MFA) on some ...
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Can someone explain the timing attack on RSA with Montgomery multiplication?
I have read several articles on the temporal attack against Montgomery multiplication to speedup RSA computations. However, I do not quite get the principle.
I understood that there is a additional ...
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Breaking ciphertext using a quantum computer when the public key is not available
As we know about Shor's algorithm on quantum computers it is possible to crack RSA / ECC easily if we have enough qubits.
Is it possible to crack RSA / ECC on a quantum computer if we only have ...
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161 views
Find prime $p$ such that $a^x\equiv b\pmod p$ for many $x\in[1,p)$
Given haphazard large integers $a$ and $b$ (like few thousand bits), can we efficiently find (and how) some integer triplet $(p,x,k)$ with
$p$ a large prime (like a thousand bits)
$a^x\equiv b\pmod p$...
