Takayuki Miyoshi

<p>Really Simple CAPTCHA does not work alone and is intended to work with other plugins. It is originally created for <a href="https://contactform7.com/" rel="nofollow ugc">Contact Form 7</a>, however, you can use it with your own plugin.</p>
<p>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.</p>
<h4>How does it work?</h4>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<h4>How to use with your plugin</h4>
<p>Note: Below are instructions for plugin developers.</p>
<p>First, create an instance of ReallySimpleCaptcha class:</p>
<pre><code>$captcha_instance = new ReallySimpleCaptcha();
</code></pre>
<p>You can change the instance variables as you wish.</p>
<pre><code>// Change the background color of CAPTCHA image to black
$captcha_instance->bg = array( 0, 0, 0 );
</code></pre>
<p>See really-simple-captcha.php if you are interested in other variables.</p>
<p>Generate a random word for CAPTCHA.</p>
<pre><code>$word = $captcha_instance->generate_random_word();
</code></pre>
<p>Generate an image file and a corresponding text file in the temporary directory.</p>
<pre><code>$prefix = wp_rand();
$captcha_instance->generate_image( $prefix, $word );
</code></pre>
<p>Then, show the image and get an answer from respondent.</p>
<p>Check the correctness of the answer.</p>
<pre><code>$correct = $captcha_instance->check( $prefix, $the_answer_from_respondent );
</code></pre>
<p>If the $correct is true, go ahead. Otherwise, block the respondent — as it would appear not to be human.</p>
<p>And last, remove the temporary image and text files, as they are no longer in use.</p>
<pre><code>$captcha_instance->remove( $prefix );
</code></pre>
<p>That’s all.</p>
<p>If you wish to see a live sample of this, you can try <a href="https://contactform7.com/captcha/" rel="nofollow ugc">Contact Form 7</a>.</p>


Really Simple CAPTCHA

Needed this for an installation with custom forms. I used the plugin developers instructions and was able to make a fully custom implementation based on server side validation within 30 minutes. No more spam bots misusing the forms. Thank you!

Great work - easy to implement

Really Simple CAPTCHA is a CAPTCHA module intended to be called from other plugins. It is originally created for my Contact Form 7 plugin.

GravityKit

<p>This Gravity Forms add-on blocks spam using a non-obtrusive anti-spam measure and can email a spam report summary.</p>
<h3>Spam blocking for Gravity Forms</h3>
<p>To get started, all you need to do is activate the plugin!</p>
<h3>Is the Gravity Forms honeypot field not working for you? 🍯 🐝</h3>
<p>Zero Spam is better than the Gravity Forms anti-spam honeypot field. If you’re getting spammed, try this plugin.</p>
<h3>Use this plugin instead of reCaptcha</h3>
<p><strong>reCaptcha is user-hostile!</strong> Use this instead! Users don’t need to click stoplights, crosswalks, or bicycles when you use this plugin to stop spam.</p>
<h3>Enable or disable filtering per form</h3>
<p>If you only want the plugin for specific forms, that’s possible! The plugin adds a simple “Prevent spam using Gravity Forms Zero Spam” setting to each form (requires Gravity Forms 2.5 or newer).</p>
<h3>Spam report emails</h3>
<p>Spam summary report emails are disabled by default. Once enabled, a spam summary that includes the number of entries per-form will be sent via email.</p>
<p>Choose whether you want to be notified after the number of entries reaches a threshold (e.g. 10 spam entries) or after a certain number of days (e.g. every week). If there are no spam entries, no report will be sent.</p>
<p>Requires <a href="https://www.gravityforms.com/?partner_id=1210629&irgwc=1&utm_medium=affiliate&utm_campaign=1210629&utm_source=Katz%20Web%20Services%2C%20Inc." rel="nofollow ugc">Gravity Forms</a>.</p>
<p><em>Brought to you by <a href="https://www.gravitykit.com?utm_source=plugin&utm_campaign=zero-spam&utm_content=readme" rel="nofollow ugc">GravityKit</a>. We create essential Gravity Forms Add-Ons.</em></p>


Gravity Forms Zero Spam

It helps way more than Gravity Forms' built in features, and it's nice to try invisible options before making users deal with Captcha quizzes. :)

Appreciate this plugin a lot!

Besides its simple approach, David Walsh’s “Zero Spam” technique, it works well.

Simple and effective

An amazingly simple yet successful strategy, this plugin captures pretty much all automated spam with little chance of false positives. No need to bother people with nasty CAPTCHAs, just install this plugin enjoy the ensuing peace.

Sends automated spam to the bit bucket

Enhance your Gravity Forms to include anti-spam measures originally based on the work of David Walsh's "Zero Spam" technique.

Really Simple CAPTCHA vs Gravity Forms Zero Spam