Advanced Google reCAPTCHA vs Really Simple CAPTCHA

Advanced Google reCAPTCHA protects your WordPress site from spam comments & brute force login attacks using captcha. This captcha plugin, quickly adds Google reCAPTCHA and other captcha tests to WordPress comment form, login form, and other forms. Using Advanced Google reCAPTCHA (most popular captcha on the market), you’ll be safe from spam comments and protect user accounts, WooCommerce, Easy Digital Downloads, BuddyPress and other forms from brute-force login attacks. reCaptcha works for: Login Form Registration Form Reset Password Form Comment Form BuddyPress Form WooCommerce Form Easy Digital Downloads (EDD) Login Form Easy Digital Downloads (EDD) Registration Form Captcha uses these 3rd party libs: Chart.js, 2017 Nick Downie, MIT DataTables, 2008-2017 SpryMedia Ltd, MIT moment.js, Tim Wood, Iskren Chernev, MIT SweetAlert 2, github.com/Sweetalert2/Sweetalert2, MIT tooltipster, www.heteroclito.fr/modules/tooltipster/, MIT

Really Simple CAPTCHA does not work alone and is intended to work with other plugins. It is originally created for Contact Form 7, however, you can use it with your own plugin. Note: This product is “really simple” as its name suggests, i.e., it is not strongly secure. If you need perfect security, you should try other solutions. How does it work? Really Simple CAPTCHA does not use PHP “Sessions” for storing states, unlike many other PHP CAPTCHA solutions, but stores them as temporary files. This allows you to embed it into WordPress without worrying about conflicts. When you generate a CAPTCHA, Really Simple CAPTCHA creates two files for it; one is an image file of CAPTCHA, and the other is a text file which stores the correct answer to the CAPTCHA. The two files have the same (random) prefix in their file names, for example, “a7hk3ux8p.png” and “a7hk3ux8p.txt.” In this case, for example, when the respondent answers “K5GF” as an answer to the “a7hk3ux8p.png” image, then Really Simple CAPTCHA calculates hash of “K5GF” and tests it against the hash stored in the “a7hk3ux8p.txt” file. If the two match, the answer is confirmed as correct. How to use with your plugin Note: Below are instructions for plugin developers. First, create an instance of ReallySimpleCaptcha class: $captcha_instance = new ReallySimpleCaptcha(); You can change the instance variables as you wish. // Change the background color of CAPTCHA image to black $captcha_instance->bg = array( 0, 0, 0 ); See really-simple-captcha.php if you are interested in other variables. Generate a random word for CAPTCHA. $word = $captcha_instance->generate_random_word(); Generate an image file and a corresponding text file in the temporary directory. $prefix = wp_rand(); $captcha_instance->generate_image( $prefix, $word ); Then, show the image and get an answer from respondent. Check the correctness of the answer. $correct = $captcha_instance->check( $prefix, $the_answer_from_respondent ); If the $correct is true, go ahead. Otherwise, block the respondent — as it would appear not to be human. And last, remove the temporary image and text files, as they are no longer in use. $captcha_instance->remove( $prefix ); That’s all. If you wish to see a live sample of this, you can try Contact Form 7.