期刊名称:Electronic Colloquium on Computational Complexity
印刷版ISSN:1433-8092
出版年度:2012
卷号:2012
出版社:Universität Trier, Lehrstuhl für Theoretische Computer-Forschung
摘要:Every pseudorandom generator is in particular a one-way function. If we only consider part of the output of the
pseudorandom generator is this still one-way? Here is a general setting formalizing this question. Suppose
G:01n01(n) is a pseudorandom generator with stretch (n)n. Let MR01m(n)(n) be a linear operator computable in polynomial time given randomness R. Consider the function
F(xR)=MRG(x)R
We obtain the following results.
- There exists a pseudorandom generator such that for every constant 1 and for an arbitrary polynomial time computable MR01(1−)n(n) , F is not one-way. Furthermore, our construction yields a tradeoff between the hardness of the pseudorandom generator and the output length m(n). For example, given =(n) and a 2cn-hard pseudorandom generator we construct a 2cn-hard pseudorandom generator such that F is not one-way, where m(n)n and +=1−o(1) .
- We show this tradeoff to be tight for 1-1 pseudorandom generators. That is, for any G which is a 2n-hard 1-1 pseudorandom generator, if +=1+ then there is MR01n(n) such that F is a (2n)-hard one-way function.