How to design a sequential hash-like function

Question

I want to develop something similar to jsfiddle in where the user can input some data and then \"save\" it and get a unique random looking url that loads that data.

Answer 1

In my opinion if you also keeping the save time of entry on server, you can generate a hash function. hash = func(id, time) but with only hash = func(id) gonna be to easy to resolve