Questions tagged [cryptographic-attack]

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5 votes
0 answers
77 views

Chosen message attack on unhashed GGH signatures?

Background: I've been reading GGH's Public-Key Cryptosystems from Lattice Reduction Problems, and have a question about a remark the authors make: "It is important to remark at the outset, that ...
11 votes
1 answer
362 views

State of research on SHA-1 Collision Attacks

SHA-1 security has been discussed since an algorithm for finding collisions was first published at CRYPTO 2004 and has been subsequently improved. Wikipedia lists a couple of references, however it ...
2 votes
1 answer
113 views

Factoring assuming smoothness of some numbers

I have came across a lot of factorization methods and most of them seem to assume smoothness of some numbers. For example When $p-1$ is smooth When $|E(\mathbb{F}_p)|$ is smooth. (Elliptic curve ...
2 votes
1 answer
106 views

Is a "complete" cipher possible?

Is a "complete" symmetric cipher possible? By this I mean a symmetric cipher that is provably secure under the assumption that a secure symmetric cipher exists.
4 votes
0 answers
103 views

Is perfect zero knowledge sequentially composable without auxiliary input?

It is known that plain and computational zero knowledge proof systems are not sequentially composable without auxiliary input (see for example http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1....
4 votes
1 answer
203 views

Cryptographic systems that don't leak linear combinations of encrypted bits

Various encryption schemes would be considered broken if an adversary could have a non-negligible edge in predicting the first (or any) bit of an encrypted message. I am looking for a slightly ...
19 votes
4 answers
692 views

How to obtain the unknown values $a_i,b_j$ given an unordered list of $a_i-b_j\mod N$?

Can anyone help me with the following problem? I want to find some values $a_i,b_j$ (mod $N$) where $i=1,2,…,K, j=1,2,…,K $ (for example $K=6$), given a list of $K^2$ values that correspond to the ...
1 vote
0 answers
277 views

Is there a better explanation of Hellman's paper on rainbow tables than the paper itself?

I'm reading through Hellman's A Cryptanalytic Time-Memory Trade-off [PDF], and I was wondering if there is code out there that implements this or if there are better explanations of how a password ...
3 votes
0 answers
180 views

Setting protocol parameters to achieve concrete security

Background One issue with modern security proofs is that they are usually asymptotic. In other words, such proofs are usually formulated as follows: For any polynomial-time adversary $\mathcal A$, we ...
6 votes
0 answers
218 views

What is the best fitness function for detecting natural language?

First, let me apologise, as this question is far from my area of expertise, but is related to a side interest (read hobby), and so this question might be very naive. This may even be off-topic for the ...
1 vote
1 answer
178 views

A clarification in Signature schemes for Strong Unforgeability.

Signature scheme is strongly unforgeable. "making the message m being signed depend on the randomness r — we break the proof of security for the underlying signature." From Paper: Strongly ...
2 votes
1 answer
627 views

Breaking encrypted file store with a file?

Let's say you have an encrypted file store of some kind such as an encrypted hard drive, ZIP file, etc. You don't have the private key or password to this file store, so a brute-force attack is not a ...
2 votes
2 answers
510 views

Can one reverse a hash with partial plaintext knowledge?

First off, please forgive my ignorance because I am not as well versed in cryptography and mathematics as I would like to be. I may say something obviously wrong/dumb; please point it out! Is there ...
1 vote
0 answers
333 views

How kerberos key distribution protocol prevents replay attack ?

How kerberos key distribution protocol prevents replay attack ?
6 votes
1 answer
268 views

Provably secure block ciphers

I have read the paper by Anderson and Biham [0] describing the ciphers Bear and Lion, which combine a PRG and a hash function (each cipher does that in a different way). the authors proved that a key ...