Displaying CAPTCHA on login screen

This plugin enables displaying CAPTCHA on login screen, ensuring that only humans can login using WebMail. Plugin makes use of Google reCAPTCHA service.
IMPORTANT: Starting from 31 Jan 2008, the plugin supports v2 of Google reCAPTCHA only.

Upon downloading and extracting plugin package, rename its main directory from:

plugin-recaptcha-master

to:

recaptcha

Then you'll need to deploy the plugin so that its index file is available at the following location:

data/plugins/recaptcha/index.php

To enable the plugin, add the following to array defined in data/settings/config.php file:

'plugins.recaptcha' => true,
'plugins.recaptcha.options.public-key' => '...',
'plugins.recaptcha.options.private-key' => '...',
'plugins.recaptcha.options.limit-count' => 0,

You'll need to supply public-key and private-key values, those are obtained at reCAPTCHA web site. The key pair can be obtained for specific domain or set of domains, there's also an option to set global key so domain doesn't make any difference.

limit-count value denotes number of unsuccessful login attempts required for CAPTCHA to be displayed. If it's set to 0, CAPTCHA is always displayed; if set to 3, it will only be displayed upon 3 failed login attempts.