Lecture 4 : Strong OWF Instructor : Rachel

Finally, we proved that the hardness of factoring implies that the inverse function (that is to say the multiplication operation or fmult(x, y)) is a weak one way function. This class will combine these definitions together. Particularly, today’s lesson will focus on proving an important theorem which states that if we are able to build a weak one-way function, then we are able to build a strong one-way function. Note that throughout this document when we say “adversary” (or “attacker”) we will always implicitly refer to a non-uniform PPT TM adversary.