wpgear

Adaptive Login Form: Adjusting compromise between Comfort and Paranoia.
Conception: 
If my current IP address is not marked as Dangerous since my last successful login, then there is no need to distrust me and force me to go through Quests to solve different types of Captchas. 
In this case, the standard “Password” field is sufficient for one attempt.
But if the Attempt is unsuccessful, then we mark the IP address as Dangerous, and then it is possible and necessary to trick me (or the one who is trying to be me) with a more thorough login procedure.
There may be multilevel options. It doesn’t matter (this will be gradually added to the functionality). We are now talking about the General Principle.
Separate statistics are generated for each IP address and the ratio “Successful number of entries” / “Total number of entries” is determined. Depending on how close this parameter is to 100%, we can talk about the need for the Toughness of the Mistrust process.
This mechanism starts before the User enters his Login.
The more Unsuccessful Login attempts occur from a given IP Address, the more thoroughly it is checked. 
Conversely, the Login procedure can be simplified as much as possible if there is no obvious reason.
<h4>Futured</h4>
<ul>
<li>Regardless of what kind of Authentication Error occurred, be it:</li>
<li>Invalid Username;</li>
<li>Invalid User Password;</li>
<li>Incorrectly specified additional security elements: “Secret Key” / Captcha / etc. 
This will not be indicated in the error message. There will always be only one message: “Authentication Failed”. 
Thus, we do not explicitly indicate to the potential Villain / Bot the reason for the denial of access. And the more such Reasons there are, the more complicated the Entry procedure becomes.</li>
<li><a href="https://wordpress.org/plugins/new-users-monitor/" rel="ugc">Integration with “New Users Monitor”</a></li>
</ul>

Adaptive Login Action

Adaptive Login Form: Adjusting compromise between Comfort and Paranoia.

greyfu

Greyfu Login Captcha adds a secure verification step to your WordPress login form, helping block automated login attempts and brute-force attacks.
Lite Version (Free): 
* Simple math-based captcha 
* Multisite compatible 
* Lightweight and fast 
* No personal data stored or transmitted 
* Works without any external service
Pro-Ready Features (Optional Upgrade): 
* Infrastructure prepared for reCAPTCHA v2 integration 
* Infrastructure prepared for hCaptcha integration 
* API key fields included
The free version is fully functional on its own and does not require any external captcha service.
<h3>Third Party Services</h3>
This plugin optionally connects to external captcha services when the Pro features are enabled:
Google reCAPTCHA (Optional) 
When reCAPTCHA is enabled in Pro settings, the plugin sends verification requests to Google’s reCAPTCHA service. 
– Service: https://www.google.com/recaptcha/ 
– Privacy Policy: https://policies.google.com/privacy 
– Terms of Service: https://policies.google.com/terms 
– Data sent: User’s IP address and reCAPTCHA response token 
– When: Only during login form submission when reCAPTCHA is enabled
hCaptcha (Optional) 
When hCaptcha is enabled in Pro settings, the plugin sends verification requests to hCaptcha service. 
– Service: https://www.hcaptcha.com/ 
– Privacy Policy: https://www.hcaptcha.com/privacy 
– Terms of Service: https://www.hcaptcha.com/terms 
– Data sent: User’s IP address and hCaptcha response token 
– When: Only during login form submission when hCaptcha is enabled
The free/lite version uses a built-in math captcha that does not connect to any external service.
<h3>Support / Contact</h3>
For issues or questions, please contact us: 
Email: hello@greyfu.com 
Website: https://greyfu.com

Greyfu Login Captcha

A lightweight captcha that protects your WordPress login page from automated bot attacks using a simple math challenge.

Adaptive Login Action vs Greyfu Login Captcha