I have difficulties checking whether $f^{-1}(x)$ is a one way function. $x \leq 2^n$ is the sum that we want the set of numbers $a_1,...,a_m$ to be. $m \leq 2^n$. There are $4^n$ different ways to sum up to a number $x$ but I did not get any further in checking if this is a one way function. Can someone help me?
$\begingroup$
$\endgroup$
1
-
1$\begingroup$ The question is unclear. What is $f$? Please don't start sentences with mathematical formulas, it's awful. And state your question in the text. Asking "Can someone help me?" is not a good question. $\endgroup$– Andrej BauerCommented Jul 5 at 11:51
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
The existence of one way functions is an open problem. As is whether the subset sum problem is solvable with a polynomial time algorithm.