# Pseudorandom Functions / Pseudorandom Permutations

I'm reading Yao's unpredictability -> pseudorandomness construction and Goldreich/levin's pseudorandom permutation -> pseudorandom generator construction.

My question is:

is there a direct way to show that:

given a pseudorandom function, we can construct a pseudorandom permutation out of it?

[or is this question open]

Thanks!

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