How does CAPTCHA know you are human?

Transcript

So how does capture work? Welcome to yet another episode of My Series, How the Hague Is That Thing Work, right teach you how the heck that thing works. Capture stands for completely automated public during tests to tell computers and humans apart. Why they couldn't come up with a better name in a shorter acronym, I am unsure. But it's those little puzzle tests that you have to do on websites to prove that you're not a cop. The image puzzle part like picking out which ones have bridges or which ones have crosswalks is only part of what the capture test is actually looking for. The other half is watching how you move your mouse and how you click on things before you even get to the test. Bots tend to move in straight lines or teleport the cursor instantly. Unfortunately, we humans do not teleport yet. We move in slightly messy curved paths. Timing matters too since a bot would solve the puzzle instantly and humans take a second to look at all the images. And that's why sometimes you just have to click a checkbox and you don't have to do any sort of puzzle at all. Love when that happens. In that case, your mouse movement and your behavior in the browser convinced it that you weren't a bot before you even got to the puzzle. The puzzle will show up if your behavior is a little bit more bot-like or if it's still not sure if you're a human or if you're a bot. Some newer versions don't require the puzzle at all and just score you based on your background behavior alone. So the picture grid isn't really the test. It's more of a backup for the cases when your behavior wasn't fully convincing enough to the capture that you aren't a human. It wasn't convinced of your humaneness. Honestly, it's just a strange amount of effort to convince something that you're not a very determined script. And Loki, I hate the ones where the pictures like keep popping up. Like, yes, I'm already selecting the crosswalks. Stop putting more pictures of crosswalks for me to click. Was I not convincing enough the first time? Let me know in the comments what you want to learn about next.

Transcribed automatically from the video, so small errors are possible.