How Does CAPTCHA Work?

How do CAPTCHA puzzles and that "I'm not a robot" box work, and are there ways for spammers to get around them?

[carmelpatrik]

its funny how we have to prove that we are not a bot to a bot who judges if we are legitimately humans

[Chris_Cross]

Soon, we're going to have self driving cars - cars that are driven by robots.

Meanwhile, the main way to prove you aren't a robot is by identifying street signs.

[astronautique]

works by tricking you if that damn character is "O" or "0"
i hate those ones

[RobinMgp]

2:32 even YouTube's auto captions got that right xD

[bugsyms]

Plot twist: The robots in CAPTCHA asking “Are you a Robot” are actually looking for their family

[ahmedshams]

The number of times i get CAPTCHA wrong, sometimes i doubt whether i am human or robot .

[biroti]

If I'm blind, how I'm supposed to click on "play audio"?

[LyricWulf]

How does Captcha work?




_It doesn't._

[brusch]

Google: "let's see how he moves the mouse"
Me: *uses touchscreen*

[StudioMoonTV]

2:31 "Gerbled to defeat automated sound analysis".

Youtube auto-generated subtitles there fucked up with system.

[liminhuang]

2:49 "in sister" wtf ??!!?!?

[sanityisoverrated]

Linus: We accept robotic viewers.

Me: View bots confirmed.

[crezey]

XD I had my auto captions on and it perfectly recognized the example audio captcha

[ZaydMenk]

But couldn't you just make a bot that moves the cursor in a squiggly way?

[KashiwaDaisuke]

still waiting for the day Captcha makes you beat Dark Souls using keyboard controls

[Hansolo]

On a smartphone, can't robots get past "I'm not a robot" verification?

[simopelle]

Even YouTube automatic subtitles recognized the Captcha audio at 2:31

[CMDrRedstone]

Why can't I just record my mouse movement and replay that? I've done it and those checkmark ones work

[josephwilkinson]

Hey Linus! Earlier this month Google updated their no-captcha reCaptcha system to allow developers to use an invisible captcha instead of even checking the box. So now it's kind of "no no captcha". I was just working on a website today when I noticed it and then you published this video.

[mosessoldaccount]

4:36 so what if you use a 4 directional joystick as an input device