Remember the game Connect the Dots we used to play as kids? It was fun and easy and you could color the pretty bunny after you were done.
This gave me an idea – a computer program doesn’t know how to play Connect the Dots very well unless it’s programmed to do just that. A computer program meant to crack normal CAPTCHAs would simply start listing the numbers appearing near the dots as the solution and be done with it.
To the left of this text you can see the output of a little program I created in a couple of hours. Given the dot coordinates for letters (on a 4×5 grid), it creates bitmaps of words from said letters. For you and me, it might take a few seconds to realize what connecting the dots gets you, but for a computer program it’s extremely hard. Add a few extra difficulties like most of today’s current CAPTCHAs have (geometric shape underlays/overlays, distortion, noise, font changes, etc.) and the fact that no CAPTCHA breaking program would expect it and you might get an (almost) unbeatable CAPTCHA.
If I only could, I’d embed it in my own weblog because comment spam here is horrible.