Who wouldn’t like the idea of cracking the lottery? Just figure out the code, and incredible riches can be yours! But the lottery is unbreakable – audited by governments, contractors, corporations, and independent agencies; or at least that’s what they want you to think.
A professional statistician named Mohan Srivastava managed to discover a flaw in certain kinds of scratch-off lottery games that allow a player to get a winning edge by doing some simple math. Wired has the whole story, and it’s well worth reading. The summary is this:
Scratch-off lottery tickets aren’t totally random. A computer prints the tickets so that a certain number are guaranteed to win – thus meeting the odds requirements set by the laws of different states. That means that a computer program has to spit out both winning and non-winning scratch-off lottery tickets. The game that Mr. Srivastava cracked had two components – a visible grid of numbers and a scratch-off section with more numbers. You play the game by scratching off the hidden section and looking for for tic-tac-toe patterns in the grid.
What Mr. Srivastava realized is that the winning tickets had a slightly different statistical distribution of data in the grid section than non-winning tickets. Knowing this, he could pick out winning tickets with 90% certainty, all without scratching a single lottery ticket.
What are some lessons for testers?
First: no system is honest or perfect, no matter what anyone claims. An audited system may have been checked for certain kinds of known flaws, but clever exploration can frequently reveal new bugs that weren’t previously known.
Second: there’s real money at stake here. The lottery generates billions of dollars in revenue for state and local governments. Having that money be put in doubt can be a serious problem. Wired also points out that a broken lottery can be a perfect system for money laundering.
Third: be honest. It’s always tempting to use your knowledge of bugs and flaws for evil, but Mr. Srivastava sets the right example for testers everywhere. He told the lottery commission about his find, and got the broken scratch-off game removed from the market.
Do you play the lottery?