checkify

Checkify helps WordPress site owners reduce CAPTCHA friction by using privacy-first human verification.
Instead of asking visitors to solve puzzles, Checkify lets visitors complete a verification flow and return a verification result to the WordPress site. This can be used on pages, forms, or custom flows where the site owner wants to request human verification or age verification.
Checkify is designed around privacy-first verification. The WordPress site receives a verification result, not unnecessary personal identity data.
<h4>Features</h4>
<ul>
<li>CAPTCHA alternative for WordPress</li>
<li>Privacy-first human verification</li>
<li>Age verification profiles (18+, 21+, 25+)</li>
<li>Site connection using a QR code</li>
<li>Local QR rendering in the browser</li>
<li>Shortcode support using [checkify_verify]</li>
<li>Live Checkify API integration</li>
<li>No external QR code generation service</li>
</ul>
<h4>How it works</h4>
<ol>
<li>Install and activate the Checkify plugin.</li>
<li>Open the Checkify settings page in WordPress.</li>
<li>Generate a connection QR code.</li>
<li>Scan the QR code in the Checkify app to connect your WordPress site.</li>
<li>Copy your Checkify Pass ID and paste it into the plugin settings.</li>
<li>Add [checkify_verify] to the page where you want to show human verification.</li>
</ol>
The shortcode creates a verification request, renders a QR code locally in the visitor’s browser, polls for verification status, and stores a temporary local verification result for that visitor.
<h3>External services</h3>
This plugin connects to Checkify services to provide human verification.
Service used:
<ul>
<li>Checkify API: https://checkify.me</li>
<li>Checkify website: https://checkify.me</li>
</ul>
The plugin connects to Checkify when:
<ul>
<li>A site administrator creates a site connection claim.</li>
<li>A site administrator polls the status of a site connection claim.</li>
<li>A connected WordPress site creates a verification request.</li>
<li>A connected WordPress site checks the status of a verification request.</li>
<li>A connected WordPress site confirms a completed verification result.</li>
</ul>
The plugin may send the following data to Checkify services:
<ul>
<li>The WordPress site domain.</li>
<li>A Checkify site identifier.</li>
<li>A Checkify installation identifier.</li>
<li>A Checkify Pass identifier configured by the site administrator.</li>
<li>Verification request identifiers.</li>
<li>Verification status tokens.</li>
<li>Request timestamps.</li>
<li>Cryptographic signatures used to authenticate the WordPress installation.</li>
</ul>
The plugin does not use an external QR code generation service. QR codes are generated locally in the visitor’s browser using the bundled QRCode.js library.
Checkify privacy policy: https://checkify.me/privacy-policy
Checkify terms: https://checkify.me/terms_and_conditions
<h3>Third-party libraries</h3>
This plugin includes QRCode.js by davidshimjs to render QR codes locally in the browser.
Library: QRCode.js
Source: https://github.com/davidshimjs/qrcodejs
License: MIT
The QRCode.js license is included in <code>qrcode-license.txt</code>.

Checkify

Replace CAPTCHA with privacy-first human verification from Checkify.

Takayuki Miyoshi

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

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.

Checkify vs Really Simple CAPTCHA