how is hashing a one way process (not reversible)?

Question

how is hashing a one way process (not reversible)?

In: 8

Answer 1

Let’s say I’m thinking of some whole number, then I run it through a function that just takes the last digit of the function. The result is 7. What number was I thinking of? Was it 17? 27? 10,573,487?

This is an example of a “one-way” function. It’s easy to figure out the answer to the input, but impossible to know what the input was based purely on the output even though you know exactly what the function does.