A colleague of mine recently interviewed for a software engineering job, and he was given a problem regarding unique identifier creation and testing for validation.
So, the problem is: if a generated unique-identifier, let's say an order id provided online by an ecommerce site, is provided to a customer, and when the customer attempts to lookup the order, they have inadvertently transposed two characters, how to quickly test that the id is invalid, and how to create an id such that the transposition of two characters does not represent another valid id.
I want to know what class of problem is this (not in the complexity sense but categorically) and what are general methods that attempt to solve it. Looking for variations on the theme of unique identifier and invalidation on google has not produced interesting results. I am hoping someone here might lead me in the right direction to learn more about this kind of problem.
I hope I have found the right forum for posing the question, and apologies if I have not.