10.1007/978-3-642-28914-9_21
Jain, Abhishek
Abhishek
Jain
Pietrzak, Krzysztof Z
Krzysztof Z
Pietrzak
Tentes, Aris
Aris
Tentes
Hardness preserving constructions of pseudorandom functions
LNCS
Springer
2012
2018-12-11T12:02:25Z
2019-08-02T12:38:07Z
conference
https://research-explorer.app.ist.ac.at/record/3279
https://research-explorer.app.ist.ac.at/record/3279.json
We show a hardness-preserving construction of a PRF from any length doubling PRG which improves upon known constructions whenever we can put a non-trivial upper bound q on the number of queries to the PRF. Our construction requires only O(logq) invocations to the underlying PRG with each query. In comparison, the number of invocations by the best previous hardness-preserving construction (GGM using Levin's trick) is logarithmic in the hardness of the PRG. For example, starting from an exponentially secure PRG {0,1} n → {0,1} 2n, we get a PRF which is exponentially secure if queried at most q = exp(√n)times and where each invocation of the PRF requires Θ(√n) queries to the underlying PRG. This is much less than the Θ(n) required by known constructions.