trustsig

TrustSig Security protects WordPress forms and API endpoints from scripted bots and brute-force attacks. No puzzles. No “I am not a robot” checkboxes. No third-party signup required to start. Coverage depends on the protection mode you choose — see “Protection modes” below.
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<h4>Why TrustSig</h4>
<ul>
<li>Protects every important form out of the box — login, registration, comments, password reset, WooCommerce checkout, BuddyPress signup, Easy Digital Downloads, Elementor Pro forms, WPForms (including the Mesmerize / Materialis contact form), Contact Form 7, SureForms, and any custom form via shortcode.</li>
<li>Stops brute-force login attempts with built-in lockout after repeated failures.</li>
<li>Invisible to humans — real visitors are verified in under a second by a non-interactive browser check. No CAPTCHA, no images to click.</li>
<li>Three protection modes — Monitor (log only), Challenge (default, soft block with auto-retry), Enforce (hard block).</li>
<li>Zero configuration — activate the plugin and protection is live immediately. Anonymous free tier needs no account.</li>
<li>Works with caching plugins, WPML, multisite and most themes — forms are signed server-side with a per-site secret.</li>
<li>Developer-friendly — PHP helper <code>trustsig_verify()</code>, REST endpoint <code>/wp-json/trustsig/v1/verify</code>, filters and actions for custom forms.</li>
<li>Optional admin-ajax and REST API guard for advanced sites.</li>
<li>GPLv2 — fully open source.</li>
</ul>
<h4>How it works</h4>
TrustSig injects a lightweight browser SDK, signs every rendered form with a per-site secret, and verifies submissions against the TrustSig Edge service. Real visitors pass an invisible check in about a second; scripted clients that never run JavaScript are stopped.
When a request arrives without a valid token, TrustSig does not silently fail 
open. Depending on the mode you choose it serves a lightweight “please wait” 
interstitial that re-verifies the browser and then transparently continues the 
original request — or blocks it.
The plugin works out of the box with no account and no API keys (anonymous 
free tier). Connecting a TrustSig dashboard account is optional and only adds 
analytics and higher limits.
<h4>Protection modes</h4>
<ul>
<li>Monitor — verify and log only, never block. Used for safe rollout; the 
upgrade path also pins existing sites here so behaviour never changes 
silently on update.</li>
<li>Challenge (default for new installs) — a missing or invalid token shows 
the interstitial, then continues or blocks.</li>
<li>Enforce — a missing or invalid token is blocked immediately.</li>
</ul>
<h4>What it protects</h4>
Browser forms are protected automatically with no code:
<ul>
<li>WordPress core — login, registration, comments, lost/reset password</li>
<li>WooCommerce — login, registration, checkout, pay order, lost password</li>
<li>BuddyPress — registration</li>
<li>Easy Digital Downloads — login, registration</li>
<li>Elementor Pro forms</li>
<li>WPForms — contact and other forms, on by default (covers the Mesmerize / Materialis contact section)</li>
<li>Contact Form 7 — feedback submissions, on by default (guarded on the REST endpoint CF7 submits to)</li>
<li>SureForms — form submissions, on by default (guarded on the REST submit-form endpoint)</li>
<li>Any other form (site-wide “protect all forms” option, the <code>[trustsig_form]</code> 
shortcode, or a hidden <code>trustsig-response</code> input)</li>
</ul>
It also includes optional brute-force lockout for repeated failed logins, an 
opt-in admin-ajax / REST API guard, and a developer verification API.
<h4>For developers</h4>
<ul>
<li>PHP: <code>trustsig_verify( array( 'token' => $t, 'action' => 'my_form' ) )</code> 
returns <code>pass</code> | <code>fail</code> | <code>challenge</code>. Filters: <code>trustsig_pre_verify</code>, 
 trustsig_result. Action: <code>trustsig_blocked</code>.</li>
<li>REST: <code>POST /wp-json/trustsig/v1/verify</code> with <code>{ "token": "..." }</code>.</li>
</ul>
<h4>Known limitations</h4>
<ul>
<li>XML-RPC (<code>xmlrpc.php</code>) is intentionally out of scope and is not verified. 
Disable XML-RPC separately if it is unused on your site.</li>
<li>admin-ajax and the REST API are only protected when explicitly enabled in 
Settings, to avoid breaking third-party integrations.</li>
<li>File-upload and AJAX submissions cannot show the interstitial; under 
Challenge or Enforce mode a missing token on those is blocked, never 
silently allowed.</li>
</ul>
<h3>External services</h3>
This plugin relies on the TrustSig Edge service to decide whether a request 
comes from a human or an automated client. This bot-detection verdict cannot be 
produced locally, so the service is required for the plugin’s core 
functionality.
Service provider: TrustSig — https://trustsig.eu
Remote script loaded in the browser: 
 https://edge.trustsig.eu/trustsig.js is loaded on pages that contain a 
protected form, on the login screen, and on the verification interstitial. The 
script runs the non-interactive browser check and produces a verification 
token.
Data sent from the visitor’s browser / your server to 
 https://edge.trustsig.eu/verify:
<ul>
<li>the TrustSig verification token generated by the SDK in the visitor’s browser;</li>
<li>your site’s host name (e.g. <code>example.com</code>) on the anonymous free tier, or, if 
you connect a dashboard account, the secret key you entered;</li>
<li>as part of any HTTPS request, the visitor’s IP address and standard request 
metadata (such as the user-agent) are visible to the service.</li>
</ul>
When data is sent: when the SDK loads on a protected page, when a protected 
form is submitted, and once per browser when the optional verified-session 
cookie is bootstrapped.
Data stored locally on your site: TrustSig writes a verification log to 
your own WordPress database (custom tables) that includes visitor IP addresses, 
the action attempted, and the verdict. This data is not sent to TrustSig; you 
can clear it at any time from Settings → TrustSig → Tools.
By installing and activating this plugin you (the site administrator) consent to 
this data being sent to TrustSig so that requests can be verified. Inform your 
own site’s visitors as required by your local privacy obligations.
<ul>
<li>Terms of Service: https://trustsig.eu/terms-of-service/</li>
<li>Privacy Policy: https://trustsig.eu/privacy</li>
</ul>

TrustSig Security


Deployment was easy, I am not tech savy but was able to get it running in less than a minute. I always had constant email spam from my site, after installing TrustSig it dropped to zero. 10/10


Easy setup and spam stopped

Stop bots, spam and brute-force attacks on every WordPress form. No CAPTCHA. No account. No keys. Installs and protects in one click.

hsarticle

HSArticle Login Math Verification protects your WordPress login page from bots and brute-force attacks using a simple math question. No Google reCAPTCHA, no Cloudflare, no API keys required.
<h4>Features</h4>
<ul>
<li>Math captcha (e.g. “8 + 5 = ?”) on the login page</li>
<li>Secure answer stored as WordPress transient (no PHP sessions)</li>
<li>Beautiful light and dark-themed login page design</li>
<li>Customizable accent color with live preview</li>
<li>Enable/disable toggle from admin settings</li>
<li>Login attempt stats (passed vs. blocked) in the admin dashboard</li>
<li>Lightweight — no external scripts loaded on the front end</li>
</ul>

HSArticle Login Math Verification

Adds a beautiful math CAPTCHA to the WordPress login page. No API keys, no paid services — 100% free.

TrustSig Security vs HSArticle Login Math Verification