computable analysis

Abstract One-way functions are the functions that are easy to compute but hard to invert. In terms of oracle Turing machines, we can formalize the notion of computable functions from reals to reals, and define it to be one-way if computable functions almost everywhere fails to invert it.

Abstract A major open problem in computational complexity is the existence of a one-way function, namely a function from strings to strings which is computationally easy to compute but hard to invert.