I now know a couple of ways: this, if a simple captcha, cut the captcha into pieces so that each piece has a symbol, then write the md5 hash of each symbol into an array along with the symbol itself. An array would look something like this:

$cap['c93d3bf7a7c4afe94b64e30c2ce39f4f'] = "2";

And then, when you need to recognize a captcha, you will need to cut it into characters and recognize the md5 of each character, compare it with the array and substitute it. But with such useless captcha sites of the unit. Therefore, there is a more horrible way: download all the captcha project and get their md5 hash. Then compare. And the values ​​of captcha will be hammered by users who want to "earn some extra money", they are given a picture, they enter, the project from which captcha, md5 captcha and meaning is written into the database. And for the introduced captcha they are paid a penny. Example: kolotibablo.com.

Now the questions:

But how on such services as "KolotiBablo" check whether the user entered the captcha correctly? Are there any other ways to recognize a captcha?
How do services like antigate.com work?
Where can I practice in cURL, otherwise strong protections are everywhere, in no way can I find a suitable training ground, and for what purpose, besides sending forms, does this library use?

Closed due to the fact that the issue is too general for the participants aleksandr barakin , VenZell , Grundy , Cerbo , cheops 23 Apr '16 at 18:54 .

Please correct the question so that it describes the specific problem with sufficient detail to determine the appropriate answer. Do not ask a few questions at once. See “How to ask a good question?” For clarification. If the question can be reformulated according to the rules set out in the certificate , edit it .

  • download all the “captcha” of the project?))) maybe I didn’t understand what, but as far as I know on less large sites they are randomly generated ... (enter no spaces, it’s just that you don’t need to be moderated by moderators in the noindex tag) Facepalm - BomBom
  • They are generated randomly almost everywhere, I’m talking about this, you look at the first specified service where you need to enter captcha for money, and the rendition does not guarantee cases without repetitions, for example echo rand (1.10) - try to refresh the page 11 times at least 1 there will be a twist. - iproger

4 answers 4

  1. Breaking Captcha
  2. We break Yandex captcha
  • Thank you, very interesting statues))) - iproger

Antigate works on the same system. People sit, your captcha comes to them, they recognize it, and send you an answer. Therefore, the Antigate service recognizes from 10 to 20 seconds. No code, only working hands :)

  • Hah, funny)) Yes this is a monkey job) - iproger

http://pixodrom.com (formerly http://anti-captcha.net) works like an antigate: you load a captcha with it through an API, they forward it to their employees, they recognize and send the answer back to the system. By captcha ID pick up the answer to your captcha.

    Sorry, but if the captcha is not elementary, no single pattern recognition system recognizes it.