<story><title>DOOM Captcha</title><url>https://vivirenremoto.github.io/doomcaptcha/</url></story><parent_chain><item><author>jandrese</author><text>While this is too simple (even the website admits that a bot could be written in virtually no time to break it), it does make me wonder if you could have a WarioWare CAPCHA.  A minigame with extremely vague description that you have to react to quickly to pass.&lt;p&gt;Thinking about it some more it fails the primary criteria for a CAPCHA: it needs to be harder to write the bot that cracks it than each test case, by at least a couple orders of magnitude.  Otherwise bot makers will just create custom bots for each contingency.  They have more time and funding than you do.</text></item></parent_chain><comment><author>GuB-42</author><text>It mostly depends on what you are trying to protect with your CAPTCHA.&lt;p&gt;When I managed a small phpbb forum, all I had to do was to change a few lines in the register page to make it non-standard and it stopped all bots. Better than the built-in CAPTCHA. Simply, no one cared enough about our forum to write a specialized tool, no matter how easy it was.&lt;p&gt;If it is all you have to protect, go ahead with your clever ideas, it can add a bit of flair to your website and stop bots effectively. For accessibility, you can always deal with special requests manually.&lt;p&gt;The problem is entirely different if you are Google. People will spend months trying to break your CAPTCHA for fun and profit. Hand crafted problems will be solved faster than they can be written so &amp;quot;bot vs bot&amp;quot; is essentially your only option.</text></comment>
<story><title>DOOM Captcha</title><url>https://vivirenremoto.github.io/doomcaptcha/</url></story><parent_chain><item><author>jandrese</author><text>While this is too simple (even the website admits that a bot could be written in virtually no time to break it), it does make me wonder if you could have a WarioWare CAPCHA.  A minigame with extremely vague description that you have to react to quickly to pass.&lt;p&gt;Thinking about it some more it fails the primary criteria for a CAPCHA: it needs to be harder to write the bot that cracks it than each test case, by at least a couple orders of magnitude.  Otherwise bot makers will just create custom bots for each contingency.  They have more time and funding than you do.</text></item></parent_chain><comment><author>lamontcg</author><text>Have the CAPCHA require properly constructing a nonlinear programming problem to solve an optimization problem, where the requirements are not expressed in terms of the NLP and the human has to design it.&lt;p&gt;Which would have the side effect of putting the bot makers to work on useful and hard problems to solve.</text></comment>