24
votes
3answers
3k views
What are the benefits of the two permutation tables in DES?
Why do we use a permutation table in the first step of DES algorithm and one at the end of algorithm?
48
votes
14answers
3k views
Time Capsule cryptography?
Does there exist any cryptographic algorithm which encrypts data in such a way that it can only be decrypted after a certain period of time?
The only idea that I can think of, is something like this: ...
20
votes
1answer
1k views
Does the generator size matter in Diffie-Hellman?
For the Diffie-Hellman protocol I've heard that the generator 3 is as safe as any other generator. Yet, 32-bit or 256-bit exponents are sometimes used as generators. What is the benefit of using ...
13
votes
4answers
557 views
Is Wiener's attack on RSA extendable to larger keys with low hamming weight?
Using small private exponents with RSA improves performance.
However, it has been shown (Wiener, 1990) that if $\log d \leq \frac14 \log N$, the private exponent $d$ can be reconstructed from the ...
5
votes
1answer
135 views
Can a proof be constructed to show there is no distinguisher?
Let's assume a simple algorithm like the Skein hash function.
Is it possible, given the algorithm, to construct a proof that it does not have a particular distinguisher, something like:
$P(xyz)$ is ...
