I learn to write captcha on the site, I don’t want to use ready-made solutions, I want to learn myself. I think you understand me. Found a lesson on creating a captcha. Tell me, please, can this captcha be used on serious projects? That is, will it protect against spam?

The lesson on this link:

Creating a PHP Captcha

    3 answers 3

    It depends on what is meant by spam. If the use of the form protected by this captcha by the robots doesn’t hope for it. It is better to protect yourself from robots with additional fields hidden from users through CSS

    • Can you tell me how to do this? - vinnie
    • For example: <style> input.email {display: none} </ style> <form ...> <input class = "email" name = "email" value = "" /> ... </ form> And accordingly if the request comes with a filled email - this is spam. - chernomyrdin
    • that is, the robot always fills all the fields, right? - vinnie
    • in 99% of cases, especially if it is email , url , etc. - chernomyrdin
    • Then it will be reliable, yes? - vinnie

    Captcha perfectly protects only in the case when no one knows about it, as soon as it goes to the masses and begins to be popular - bots are written under it.

    More or less (IMHO) the working method is a unique question-answer, everything else is crap.

      Captcha is a dead end approach. Need something new! :)

      PS: on the topic, captcha elementary, breaks without any problems whatsoever by standard means :)

      • Explain the amateur. Break substitution in SESSION MD5 in accordance with the Input? If so, can it be broken if MD5 is put into a local file (or base), and in SESSION is the name of this file put? - avp
      • No, I meant that the text recognized by the bot depicted on the captcha is recognized - Alex Kapustin
      • And how you can break the captcha? I only knew about bots-discriminators, but you don’t recognize difficult captchas, for example, like in Yandex. - iproger
      • >> but difficult captchas, for example, like Yandex, you do not recognize. This is a myth :) - Alex Kapustin