A cryptographic hash algorithm is a function which takes a variable size input and produces a fixed size output. The algorithm makes it difficult to predict the output for a given input, find two inputs with the same output, or reconstruct the input from the output.
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Are there any practical implementation of a homomorphic hashing or signature scheme?
A homomorphic hash function is a function $H : A \to B$ between two sets with some algebraic structure $(A, *)$ and $(B, \star)$ such that
$H$ is collision resistant, i.e. it is hard to find $x \neq ...
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MD4 First preimage - state of the art
What's the state of the attack to get the first preimage on MD4?
Is it still this http://www.di.ens.fr/~leurent/files/MD4_FSE08.pdf in 2^102 ?
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Pseudo preimage for a hash made from a cipher
Consider the Miyaguchi–Preneel construction:
$H_0 = E(0,m_0) \oplus m_0$ (0 here means a vector filled with zeros)
$H_1 = E(H_0,m_1) \oplus H_0 \oplus m_1$
where $E(K,M)$ is a block cipher (for ...
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LT codes with Homomorphic hashing
I have been working on a project implementing LT codes with Homomorphic hashing (inspired from http://blog.notdot.net/2012/08/Damn-Cool-Algorithms-Homomorphic-Hashing and ...
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How can I prove that this encryption scheme from a random oracle is secure?
I am reading this example:
A random oracle is an ideal object.
What makes a random oracle convenient for proofs is the part about knowing nothing on the output for a given input if you do not ...
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How do you construct a practical full-domain hash function?
I am looking for practical constructions for Full Domain Hash.
I have read Random Oracles are Practical by M. Bellare and P. Rogaway, the construction suggested on page 8, under "Uniformity: a ...
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Does Keccak have an eTCR mode?
On page 7 of NIST's views on SHA-3's security requirements and Evaluation of attacks, I see that, at least at this point, NIST planned on offering SHA-3 having eTCR security (defined on page 3):
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P-Complete hashes, hashing to a larger set
Historically hashes have been from a large set (say 256 characters) to a smaller set (256 bits).
Also, hash functions that are P-complete have no known parallel algorithm; they must be computed ...
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How hard is a known prefix hash preimage attack?
Suppose the attacker knows X, Z such that
H(X || Y) = Z
If bit-length(Y) < 60 then a brute force attack is possible.
What if
bit-length(Z) = 256 (such as in SHA-256)
bit-length(X) = 128
...
