All Questions
6 questions
6
votes
1
answer
418
views
Groups in which Computational Diffie Hellman is in $P$ but Discrete Logarithm is not known to be in $P$
The Computational Diffie Hellman (CDH) problem is to compute $g^{XY}$ given $g^X$ and $g^Y$ where $g$ generates the group. The Discrete Logarithm (DLOG) problem is to compute $X$ given $g^X$. The ...
3
votes
1
answer
138
views
Given $n, c$ find $a>1,b$ such that $b ^ a \equiv c \pmod n$
Given a natural number $n$ (of unknown factorization) and an arbitrary number $c \in \mathbb{Z}^*_n$ (the set of natural numbers smaller than $n$ and coprime to it), is there an efficient algorithm ...
3
votes
1
answer
164
views
Mestre-type algorithm for higher-genus curves?
Is there an analogous algorithm for genus $g>2$ curves that, given a complete set of invariants, outputs a curve with those invariants?
(I'm interested in particular in $g=3$.)
Any references ...
2
votes
1
answer
162
views
DL-problem on abelian variety
Let $A$ be an abelian variety over $\mathbb{F_q}$ with dimension $n$. Let $q$ be a constant.
Is there polynomial algorithm of finding discrete logarithm in $A$?
UPD: really I don't undestend: can we ...
23
votes
5
answers
1k
views
Securing privacy of "who communicates with whom" under Orwell-like conditions
Assume that there is a big and powerful country with an
information-greedy secret service which has backdoors to all internet nodes
throughout the world which permit him to observe all exchanged data ...
2
votes
3
answers
398
views
Generating a set of integer passwords that can be securely authenticated
First, apologies for the title. This is an odd question, and I couldn't come up with a simple title for it.
My question is as follows.
Given a positive integer $k$, determine a set of properties $S$ ...