One-way function
In computer science, a one-way function is a function that is easy to compute on every input, but hard to invert given the image of a random input.[2]
One-way function. One-way functions are easy to compute but it is very difficult to compute their inverse functions. ... One-way functions are key elements of various tools useful in modern cryptography. They are used in pseudorandom generators, authentication of messages and digital signatures.[3]