Ideas to create a small (<10 digits), not (very) secure “hash”

Question

I\'m working on an online event ticketing system, where users will be able to self print his tickets and show up at the event where it will be scanned (barcode) and ideally

Answer 1

Two ways I can see:

1. Generate a random number, or at least a random part for a number, and store it in a central database. Then download the database into all the gate systems to check against.
2. The number has to be self-sufficient. In other words, the number has to be able to check out without the saved list. This sounds like some kind of checksum system. For instance, you could issue numbers from 1 and upwards, make them 5 digits (00000-99999 = 100.000 numbers), and prepende 1-3 letters, making sure you end up with a checksum that would check out.