# Tag Info

8

NO, we can't apply an hill-climbing algorithm to Diffie–Hellman. In order to break Diffie-Hellman key exchange, it is enough for Eve to reverse exponentiation modulo the public prime $p$; that is, given $g^x\bmod p$, find $x$. That's the Discrete Logarithm Problem. We do not know that hill-climbing can help for that (or the slightly less general DH ...

7

Grover's algorithm treats the function it is evaluating as a black box and finds, with high probability, an input to the black box such that it outputs a specified value in $O(N^{1/2})$ evaluations of the function. Since Grover's algorithm works on the function as a black box, your modification does not hinder Grover's algorithm at all in finding the ...

3

First, I would like to point you to this answer. Copying the TL;DR from there: Multiple encryption addresses a problem that mostly doesn't exist. You are better off using a single well chosen algorithm. That said, here are answers to some of your questions: A longer password adds more layers of encryption in this hypothetical scenario and thus ...

2

Because groups used for Diffie-Hellman cannot be given a non-trivial, efficiently calculable metric, you cannot define such things like a "local maximum" or "local minimum". You also cannot say if you are climbing or diving.

2

No, it is not always bijective. A perfect hash guarantees that no two inputs (from the set of valid inputs) collides, so it is clearly a 1 to 1 mapping. However, in the case where the output range contains more possible values than there were valid inputs, there will be outputs which do not map back to inputs. hence it is not bijective. If you restrain ...

1

The injective hash function wikipedia referes to is not a secure hash function for cryptographic purposes. It is a hash function used for fast database access. An ideal secure hash function is a random oracle and a random oracle is not injective with very high probability.

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