Questions tagged [collision-attack]

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Is WPA2 collision-proof?

I was experimenting with hashcat and aircrack to test WiFi security. The WiFi AP is a WPA2 encrypted network. The tool I used to ...
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2 votes
1 answer
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Chosen Plain text attack [closed]

I have a course work for university, the question is: Consider a symmetric encryption scheme with its encryption operation written as $$C = E(K, R||P)$$ where $E$ is a block cipher encryption ...
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1 answer
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MITM against NTRU

In MITM attacks against the NTRU cryptosystem, we exploit the fact that in the ring of truncated polynomials of degree $n-1$ it holds that $$fg=h\mod q$$ for our secret and public keys $f,h$. The ...
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Detecting MD5sum collision vulnerability?

It's my understanding that MD5 is still resistant to preimage attacks in the general case, but that an attacker may still launch a second preimage attack if an innocent file is "unlucky" ...
1 vote
1 answer
139 views

Does deriving a key from a master key and then encrypting with AES-GCM increase the lifetime of the master key?

Suppose that we have a symmetric 256-bit master key, and we want to encrypt using AES-GCM with random IVs. I understand that with random IVs, the lifetime of the master key is 2^32 in order to conform ...
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Checking if a function is collision-resistant

Consider a prime order cyclic group $\Bbb G$ of order $q$ with generator $g$. Then consider the function$$f:\Bbb Z^n_q\to\Bbb G\\(\alpha_1,\alpha_2,...,\alpha_n)\mapsto g^{\alpha_1\cdot\alpha_2...\...
1 vote
1 answer
217 views

Are these both the probability of collision in birthday attack?

About birthday attack, book Cryptography Engineering says: In general, if an element can take on N different values, then you can expect the first collision after choosing about $\sqrt{N}$ random ...
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2 votes
1 answer
587 views

Understanding Hash collisions - why bad?

I read few answers about the question: why are hash collisions so dangerous? But did not get a really satisfying answer. Assume we are the first people who found a SHA256-collision, like sha256($§&...
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2 votes
2 answers
1k views

Is there collision in encryption like in hash functions?

In hash functions, $h(m) = h(m_1)$ is called collision and is very undesired that they are feasible to find as it undermines hash security. However, is there essentially analogous concern in ...
3 votes
1 answer
91 views

How would a malicious group of co-signers use a hash collision to sign an unintended message?

According to BIP340: However, a major drawback of this optimization is that finding collisions in a short hash function is easy. This complicates the implementation of secure signing protocols in ...
3 votes
1 answer
238 views

Collision finding method

The "birthday paradox" places an upper bound on collision resistance: if a hash function produces $N$ bits of output, an attacker who computes only $2^{N/2}$ (...) hash operations on random ...
0 votes
2 answers
188 views

Does google's Shattered paper(The first collision for full SHA-1) mean creating a new file with the same hash as the original file?

I have a source data A and a hash H(A) of this A. Is it possible by google's shattered docs to create a new data B that outputs this H(A)? ++ I understood that the content of the paper is to ...
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2 answers
562 views

Is it possible to get the SHA256 hash collision with partial known data

I have a text sentence that consists of 448 digits [0-9] [a-f] (in HEX format). This text sentence is partially cut off, but I know the middle, and the beginning ...
1 vote
3 answers
139 views

Hash function collision importance

Suppose a collision has been found in a certain hash function, such that H(x1) = H(x2) However, x1 and x2 are both a seemingly 'random' collection of bits which do not convey a coherent message, and ...
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1 vote
1 answer
99 views

Is recursive hashing cyclic?

If I feed the output of H back into H will it cover the entire output space of H before repeating? Consider the following scenario: ...
3 votes
2 answers
1k views

How easy is it to fake a file hashed with three functions, CRC32, MD5 and SHA-1?

File-A is hashed with CRC32, MD5 and SHA-1. How easy is it to create a fake file-B that has the same hashes of file-A? CRC32, MD5 and SHA-1? Can an average PC with a GPU calculate a triple hash ...
2 votes
1 answer
64 views

Finding $k$ strings $M_i$ such the XOR of the $k$ hashes $H(i,M_i)$ is zero

Let $k\ge2$ be a moderate given constant, and $H:[0,k)\times\{0,1\}^*\to\{0,1\}^b$ be a $b$-bit given hash function assimilated to a random oracle. For example $H(i,M)=\operatorname{SHAKE256}((\...
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