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I am Guest A. I posted as a guest because I was too lazy to log in to my Stack Exchange account. If you end up selecting my previous answer, please do it to this answer instead, so i can get the reputation. I read somewhere that reCAPTCHAs use the movement of the mouse (only in their area) to determine if you area bot or not. Try this - use mouse keys on ...


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I read somewhere that reCAPTCHAs use the movement of the mouse (only in their area) to determine if you area bot or not. Try this - use mouse keys on your computer (if it is windows use Left-Alt + Left-Shift + NumLock) to move the mouse straight up. Does this trigger the image selection?


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Google tries to figure out if you are a bot or not. If it's in doubt, it serves you a CAPTCHA to check. Exactly how this is done is part of Googles secret sauce, and I don't think they will tell you. But here are some ingredients I guess that they mix together: Your IP: Has it been identified as a bot already? Is it a Tor exit node? The resources you load: ...


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If it is a secure CAPTCHA, the AJAX message will send the user's input to a server. The server will validate the input and return a token. The token will then be inserted into the form by the Javascript. When the form is submitted, the server will validate the token with the CAPTCHA service (this could be a web service call or signature validation). So the ...


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If the validation (i.e. cheching that the user input matches the text on the CAPTCHA) is done client side, nothing is stopping you from bypassing it. You dont even have to read the code - just look at the HTTP request the AJAX send and copy it. This can be done with the developer tool in any browser. A very basic rule for web security is to never trust the ...


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The challenge you're describing (select images that meet criteria) is actually two machine problems. 1: figure out what it wants (somehow parse "select all images that contain water" or the more difficult, find out what's in an image and "match" it to similar pictures of something, i.e. a turkey) and then 2: figure out how to categorize images (tell which ...


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People have been moderately successful at attacking these with OCR software and a variety of other non-OCR techniques. They do still slow automated attackers some so they are still very useful but they have been proven to be broken as a true test of human vs. machine for quite a while. The following related links may be of use: ...



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