Jehy

<a href="https://wordpress.org/plugins/securimage-wp-fixed/" rel="ugc">Securimage-WP-Fixed</a> utilizes the powerful CAPTCHA protection of <a href="http://phpcaptcha.org/" title="Securimage PHP CAPTCHA" rel="nofollow ugc">Securimage Captcha</a> which adds protection to your WordPress comment forms. Unfortunately, it didn’t have option to be installed on user register page. Now you can just install Securimage-WP-REG, enable it – and you will have CAPTCHA on register page!
So, Securimage-WP-REG adds captcha on register pages.
Requirements:
<ul>
<li><a href="https://wordpress.org/plugins/securimage-wp-fixed/" rel="ugc">Securimage-WP-Fixed</a> plugin installed and working. Old version of this plugin you can find <a href="https://www.phpcaptcha.org/download/wordpress-plugin/" rel="nofollow ugc">here</a>.</li>
</ul>
<h4>Donate or help?</h4>
If you want to ensure the future development and support of this plugin, you can make donation <a href="http://jehy.ru/articles/donate/" rel="nofollow ugc">on this page</a> or just write about this plugin in your blog.

Securimage-WP-REG

Securimage-WP-REG adds captcha ptotection from Securimage-WP plugin on register pages.

Ralf Weber

No more SPAM by spiders scanning you site for email addresses. With CryptX you can hide all your email addresses, with and without a mailto-link, by converting them using javascript or UNICODE.
CryptX protects your email addresses from spam bots while keeping them readable and functional for your visitors. The plugin automatically detects email addresses in your content and encrypts them using various methods including JavaScript encryption, Unicode conversion, and image replacement.
Key Features:
<ul>
<li>Automatic Email Detection – Finds and encrypts email addresses in posts, pages, comments, and widgets</li>
<li>Multiple Encryption Methods – JavaScript, Unicode, image replacement, and custom text options</li>
<li>Widget Support – Works with text widgets and other widget content</li>
<li>RSS Feed Control – Option to disable encryption in RSS feeds</li>
<li>Whitelist Support – Exclude specific domains from encryption</li>
<li>Per-Post Control – Enable/disable encryption on individual posts and pages</li>
<li>Shortcode Support – Use <code>[cryptx]email@example.com[/cryptx]</code> for manual encryption</li>
<li>Template Functions – Developer-friendly functions for theme integration</li>
</ul>
<a href="http://weber-nrw.de/wordpress/cryptx/" title="Plugin Homepage" rel="nofollow ugc">Plugin Homepage</a>

CryptX

No more SPAM by spiders scanning you site for email addresses!

Securimage-WP-REG vs CryptX