captcha 

Author: Samir Shah Akismet is great at detecting spam, but if you get lots of it then it means trawling through the spam queue in case there are any false positives
Installation:
Upload the wp-conditional-captcha folder to the /wp-content/plugins/ directory (or use the Wordpress auto-install feature) Activate the plugin through the Plugins menu in WordPress The settings for the plugin can be accessed from the Plugins administration menu.
faq:
Ive installed it, now how do I check that it works? You can try posting a spammy comment on your blog (make sure youre logged out) to check that it works, and to see what it looks like. Posting a comment with something like [url]somethingsilly[/url] in the body will usually get it flagged by Akismet. Does this plugin work with PHP 4? Sorry, it doesnt. Please use it only with PHP 5.0 and above. Does this plugin work with other comment form modification plugins? Conditional CAPTCHA relies on Wordpress native form handling procedures. This means it will not work with plugins that generate and process their own comment forms. Such plugins include WP AJAX Edit Comments, tdo-miniforms and Contact Form 7.

Author: Deformed Design There are a lot of great plugins to prevent spam but especially the effectiv captcha images can annoy your human visitors. Geo Captcha uses the knowledge that a lot of spam is caused from a few countries and prevents them from spamming
Installation:
Upload geo-captcha-folder to the /wp-content/plugins/ directory Activate the plugin through the Plugins menu in WordPress Set up the whitelist in the Geo Captcha Settings Usage You can activate and deactivate the geocaptcha function for comments and registration in the settings. Add the country codes of the countries you dont want to insert a captcha to the list in the plugins settings. Check you log to see the countries which cause a lot of spam or who are false positivs.

Author: Mike Challis Adds CAPTCHA anti-spam methods to WordPress on the comment form, registration form, login, or all. In order to post comments or regiser, users will have to type in the phrase shown on the image. This prevents spam from automated bots. Adds security. Works great with Akismet. Also is fully WPMU and BuddyPress compatible
Installation:
Upload the si-captcha-for-wordpress folder to the /wp-content/plugins/ directory, or download through the Plugins menu in WordPress Activate the plugin through the Plugins menu in WordPress Updates are automatic. Click on "Upgrade Automatically" if prompted from the admin menu. If you ever have to manually upgrade, simply deactivate, uninstall, and repeat the installation steps with the new version. This is how to install SI Captcha globally on WPMU or BuddyPress: Step 1: upload the /si-captcha-for-wordpress/ folder and all its contents to /mu-plugins/ Step 2: MOVE the si-captcha.php from the /si-captcha-for-wordpress/ folder to the /mu-plugins/ folder. Site wide Settings are located in "Site Admin", "SI CAPTCHA Optioins"
faq:
Sometimes the captcha image and captcha input field are displayed AFTER the submit button on the comment form. Your theme must have a <?php do_action(comment_form, $post->ID); ?> tag inside your comments.php form. Most themes do. The best place to locate the tag is before the comment textarea, you may want to move it if it is below the comment textarea. This tag is exactly where the captcha image and captcha code entry will display on the form, so move the line to before the comment textarea, uncheck the Comment Form Rearrange box on the Captcha options page, and the problem should be fixed. Alternate Fix for the captcha image display order You can just check the Comment Form Rearrange box on the admin plugins Captcha options page and javascript will attempt to rearrange it for you. Editing the comments.php, moving the tag, and uncheck the Comment Form Rearrange box on the Captcha options page is the best solution. Why is it better to uncheck the Comment Form Rearrange box and move the tag? Because the XHTML will no longer validate if it is checked. Why do I get "ERROR: Could not read CAPTCHA cookie. Make sure you have cookies enabled and not blocking in your web browser settings. Or another plugin is conflicting."? Check your web browser settings and make sure you are not blocking cookies for your blog domain. Cookies have to be enabled in your web browser and not blocked for the blog web domain. If you get this error, your browser is blocking cookies or you have another plugin that is conflicting (in that case I would like to help you further to determine which one). I can tell you that the plugin called "Shopp" is not compatible because it handles sessions differently causing the "ERROR: Could not read CAPTCHA cookie. Make sure you have cookies enabled". The Cookie Test can be used to test if your browser is accepting cookies from your site: Click on the "Test if your PHP installation will support the CAPTCHA" link on the Options page. or open this URL in your web browser to run the test: /wp-content/plugins/si-captcha-for-wordpress/captcha-secureimage/test/index.php Troubleshooting if the CAPTCHA form fields and image is not being shown: Do this as a test: Activate the SI CAPTCHA plugin and temporarily change your theme to the "Wordpress Default" theme. Does the captcha image show now? If it does then the theme you are using is the cause. Your theme must have a <?php do_action(comment_form, $post->ID); ?> tag inside your comments.php form. Most themes do. The best place to locate the tag is before the comment textarea, you may want to move it if it is below the comment textarea. This tag is exactly where the captcha image and captcha code entry will display on the form, so move the line to before the comment textarea, uncheck the Comment Form Rearrange box on the Captcha options page, and the problem should be fixed. Troubleshooting if the CAPTCHA image itself is not being shown: By default, the admin will not see the CAPTCHA. If you click "log out", go look and it will be there. If the image is broken and you have the CAPTCHA entry box: This can happen if a server has too low a default permission level on new folders. Check and make sure the permission on all the captcha-secureimage folders are set to permission: 755 all these folders need to be 755: - si-captcha-for-wordpress - captcha-secureimage - audio - gdfonts - images - test Here is a tutorial about file permissions This script can be used to test if your PHP installation will support the CAPTCHA: Click on the "Test if your PHP installation will support the CAPTCHA" link on the Options page. or open this URL in your web browser to run the test: /wp-content/plugins/si-captcha-for-wordpress/captcha-secureimage/test/index.php Is this plugin available in other languages? Yes. To use a translated version, you need to obtain or make the language file for it. At this point it would be useful to read Installing WordPress in Your Language from the Codex. You will need an .mo file for this plugin that corresponds with the "WPLANG" setting in your wp-config.php file. Translations are listed below -- if a translation for your language is available, all you need to do is place it in the /wp-content/plugins/si-captcha-for-wordpress/languages directory of your WordPress installation. If one is not available, and you also speak good English, please consider doing a translation yourself (see the next question). The following translations are included in the download zip file: Albanian (sq_AL) - Translated by Romeo Shuka Arabic (ar) - Translated by Amine Roukh Belorussian (by_BY) - Translated by Marcis Gasuns Chinese (zh_CN) - Translated by Awu Czech (cs_CZ) - Translated by Radovan Danish (da_DK) - Translated by Parry French (fr_FR) - Translated by Pierre Sudarovich German (de_DE) - Translated by Sebastian Kreideweiss Greek (el) - Translated by Ioannis Italian (it_IT) - Translated by Gianni Diurno Norwegian (nb_NO) - Translated by Roger Sylte Polish (pl_PL) - Translated by Tomasz Portuguese Brazil (pt_BR) - Translated by [Newton Dan Faoro] Russian (ru_RU) - Translated by Neponyatka Spanish (en_ES) - Translated by LoPsT Swedish (sv_SE) - Translated by [Benct] Traditional Chinese, Taiwan Language (zh_TW) - Translated by [Cjh] Turkish (tr_TR) - Translated by Volkan More are needed... Please help translate. Are the CAPTCHA audio files available in other languages? Portuguese brazil (pt_BR) audio files are available. Wait until after you install the plugin. Download the audio files: Portuguese brazil (pt_BR) audio files download and follow instructions in the Readme.txt inside the zip file. Can I provide a translation? Of course! It will be very gratefully received. Use PoEdit, it makes translation easy. Please read Translating WordPress first for background information on translating. Then obtain the latest .pot file and translate it. * There are some strings with a space in front or end -- please make sure you remember the space! * When you have a translation ready, please send the .po and .mo files to wp-translation at 642weather dot com. * If you have any questions, feel free to email me also. Thanks! Is it possible to merge the translation files I sent to you with the ones of the newest version? If you use PoEdit to translate, it is easy to translate for a new version. You can open your current .po file, then select from the PoEdit menu: "Catalog" > "Update from POT file". Now all you have to change are the new language strings.

Author: Mike Challis Adds CAPTCHA anti-spam methods to WordPress on the comment form, registration form, login, or all. In order to post comments or regiser, users will have to type in the phrase shown on the image. This prevents spam from automated bots. Adds security. Works great with Akismet. Also is fully WPMU and BuddyPress compatible
Installation:
Upload the si-captcha-for-wordpress folder to the /wp-content/plugins/ directory, or download through the Plugins menu in WordPress Activate the plugin through the Plugins menu in WordPress Updates are automatic. Click on "Upgrade Automatically" if prompted from the admin menu. If you ever have to manually upgrade, simply deactivate, uninstall, and repeat the installation steps with the new version. This is how to install SI Captcha globally on WPMU or BuddyPress: Step 1: upload the /si-captcha-for-wordpress/ folder and all its contents to /mu-plugins/ Step 2: MOVE the si-captcha.php from the /si-captcha-for-wordpress/ folder to the /mu-plugins/ folder. Site wide Settings are located in "Site Admin", "SI CAPTCHA Optioins"
faq:
Sometimes the captcha image and captcha input field are displayed AFTER the submit button on the comment form. Your theme must have a <?php do_action(comment_form, $post->ID); ?> tag inside your comments.php form. Most themes do. The best place to locate the tag is before the comment textarea, you may want to move it if it is below the comment textarea. This tag is exactly where the captcha image and captcha code entry will display on the form, so move the line to before the comment textarea, uncheck the Comment Form Rearrange box on the Captcha options page, and the problem should be fixed. Alternate Fix for the captcha image display order You can just check the Comment Form Rearrange box on the admin plugins Captcha options page and javascript will attempt to rearrange it for you. Editing the comments.php, moving the tag, and uncheck the Comment Form Rearrange box on the Captcha options page is the best solution. Why is it better to uncheck the Comment Form Rearrange box and move the tag? Because the XHTML will no longer validate if it is checked. Why do I get "ERROR: Could not read CAPTCHA cookie. Make sure you have cookies enabled and not blocking in your web browser settings. Or another plugin is conflicting."? Check your web browser settings and make sure you are not blocking cookies for your blog domain. Cookies have to be enabled in your web browser and not blocked for the blog web domain. If you get this error, your browser is blocking cookies or you have another plugin that is conflicting (in that case I would like to help you further to determine which one). I can tell you that the plugin called "Shopp" is not compatible because it handles sessions differently causing the "ERROR: Could not read CAPTCHA cookie. Make sure you have cookies enabled". The Cookie Test can be used to test if your browser is accepting cookies from your site: Click on the "Test if your PHP installation will support the CAPTCHA" link on the Options page. or open this URL in your web browser to run the test: /wp-content/plugins/si-captcha-for-wordpress/captcha-secureimage/test/index.php Troubleshooting if the CAPTCHA form fields and image is not being shown: Do this as a test: Activate the SI CAPTCHA plugin and temporarily change your theme to the "Wordpress Default" theme. Does the captcha image show now? If it does then the theme you are using is the cause. Your theme must have a <?php do_action(comment_form, $post->ID); ?> tag inside your comments.php form. Most themes do. The best place to locate the tag is before the comment textarea, you may want to move it if it is below the comment textarea. This tag is exactly where the captcha image and captcha code entry will display on the form, so move the line to before the comment textarea, uncheck the Comment Form Rearrange box on the Captcha options page, and the problem should be fixed. Troubleshooting if the CAPTCHA image itself is not being shown: By default, the admin will not see the CAPTCHA. If you click "log out", go look and it will be there. If the image is broken and you have the CAPTCHA entry box: This can happen if a server has too low a default permission level on new folders. Check and make sure the permission on all the captcha-secureimage folders are set to permission: 755 all these folders need to be 755: - si-captcha-for-wordpress - captcha-secureimage - audio - gdfonts - images - test Here is a tutorial about file permissions This script can be used to test if your PHP installation will support the CAPTCHA: Click on the "Test if your PHP installation will support the CAPTCHA" link on the Options page. or open this URL in your web browser to run the test: /wp-content/plugins/si-captcha-for-wordpress/captcha-secureimage/test/index.php Is this plugin available in other languages? Yes. To use a translated version, you need to obtain or make the language file for it. At this point it would be useful to read Installing WordPress in Your Language from the Codex. You will need an .mo file for this plugin that corresponds with the "WPLANG" setting in your wp-config.php file. Translations are listed below -- if a translation for your language is available, all you need to do is place it in the /wp-content/plugins/si-captcha-for-wordpress/languages directory of your WordPress installation. If one is not available, and you also speak good English, please consider doing a translation yourself (see the next question). The following translations are included in the download zip file: Albanian (sq_AL) - Translated by Romeo Shuka Arabic (ar) - Translated by Amine Roukh Belorussian (by_BY) - Translated by Marcis Gasuns Chinese (zh_CN) - Translated by Awu Czech (cs_CZ) - Translated by Radovan Danish (da_DK) - Translated by Parry French (fr_FR) - Translated by Pierre Sudarovich German (de_DE) - Translated by Sebastian Kreideweiss Greek (el) - Translated by Ioannis Italian (it_IT) - Translated by Gianni Diurno Norwegian (nb_NO) - Translated by Roger Sylte Polish (pl_PL) - Translated by Tomasz Portuguese Brazil (pt_BR) - Translated by [Newton Dan Faoro] Russian (ru_RU) - Translated by Neponyatka Spanish (en_ES) - Translated by LoPsT Swedish (sv_SE) - Translated by [Benct] Traditional Chinese, Taiwan Language (zh_TW) - Translated by [Cjh] Turkish (tr_TR) - Translated by Volkan More are needed... Please help translate. Are the CAPTCHA audio files available in other languages? Portuguese brazil (pt_BR) audio files are available. Wait until after you install the plugin. Download the audio files: Portuguese brazil (pt_BR) audio files download and follow instructions in the Readme.txt inside the zip file. Can I provide a translation? Of course! It will be very gratefully received. Use PoEdit, it makes translation easy. Please read Translating WordPress first for background information on translating. Then obtain the latest .pot file and translate it. * There are some strings with a space in front or end -- please make sure you remember the space! * When you have a translation ready, please send the .po and .mo files to wp-translation at 642weather dot com. * If you have any questions, feel free to email me also. Thanks! Is it possible to merge the translation files I sent to you with the ones of the newest version? If you use PoEdit to translate, it is easy to translate for a new version. You can open your current .po file, then select from the PoEdit menu: "Catalog" > "Update from POT file". Now all you have to change are the new language strings.

Author: Michael L Wells This plugin was developed primarily for the WordPress Muti-User edition, however it works on the regular single domain version as well. It combats spam bots from flooding you with sign-ups and blog creations and it keeps bots from brute- force attacking your site with the admin username by forcing a visual confirmation CAPTCHA in order to login
Installation:
Upload the super-captcha folder and ALL its contents to the /wp-content/plugins/ directory If you wish to customize your audio files or word.txt files for custom words and more security, change these files under the super-captcha/includes directory before upload and install. Activate the plugin through the Plugins menu in WordPress CAPTCHA Ready -- Easy as that.
faq:
Does this Plugin have any configurable options through the admin panel? Loads! Check the sCAPTCHA Menu (in its on box). OMG! I just hosed my CAPTCHA when updating a config option! What do I do?!? Step 1: Chill, Ive already thought about that, and Step2: Under your Config options, youll see a big white button that says, Restore Defaults; click it -- enjoy. I just installed this software and spam bots are still eating up my MU site, what did I do wrong? Under the sCAPTCHA menu, you did not set it to display on the "Sign Ups"... Set that and click "Save Settings" then smile as the spam bots dont know what to do =) I recommend also ticking the display on login as well. I installed it, as instructed, and the image does not show up! Whats wrong? Your server is not allowing or does not support FreeType or PHPs GD2 Library. See www.php.net for more information. Ive installed this plugin and now I cant login to my admin panel. Help! Rename /wp-content/plugins/super-captcha/ to wp-content/plugins/super-captcha.bk/ to forcefully deactivate the plugin to restore access and let us know at http://www.mlwassociates.com/products/super-capcha/ Ok this plugin is awesome, but I dont see how I can donate? We allow donations but we are a profitable company (partnership rather) so though theyre not tax deductable, you will have to contact us in order to "support" (not donate btw) our open source projects. 100% of any funding given by support of an open source project goes dirrectly into paying developers to work on them, tweak them, and make them secure and bug free. Do you guys offer any other plugins? Yes, but not all are GPL or GNU, theyre licensed through a proprietary licnese, though youll get full access to the source code, the other software took loads of time to create so theyre for sale.

Author: Andrey Sorvin Smart invisible captcha for wordpress comments. This small plugin protects your blog from a spam in comments
Installation:
Upload invisible_captcha.php to the /wp-content/plugins/invisible_captcha/ directory Activate the plugin through the Plugins menu in WordPress The important remark: The Identifier of the button for comment sending in your comment-page should be "submit".

Author: Mike Challis Adds CAPTCHA anti-spam methods to WordPress on the comment form, registration form, login, or all. In order to post comments or regiser, users will have to type in the phrase shown on the image. This prevents spam from automated bots. Adds security. Works great with Akismet. Also is fully WPMU and BuddyPress compatible
Installation:
Upload the si-captcha-for-wordpress folder to the /wp-content/plugins/ directory, or download through the Plugins menu in WordPress Activate the plugin through the Plugins menu in WordPress Updates are automatic. Click on "Upgrade Automatically" if prompted from the admin menu. If you ever have to manually upgrade, simply deactivate, uninstall, and repeat the installation steps with the new version.
faq:
Sometimes the captcha image and captcha input field are displayed AFTER the submit button on the comment form. Your theme must have a <?php do_action(comment_form, $post->ID); ?> tag inside your comments.php form. Most themes do. The best place to locate the tag is before the comment textarea, you may want to move it if it is below the comment textarea. This tag is exactly where the captcha image and captcha code entry will display on the form, so move the line to before the comment textarea, uncheck the Comment Form Rearrange box on the Captcha options page, and the problem should be fixed. Alternate Fix for the captcha image display order You can just check the Comment Form Rearrange box on the admin plugins Captcha options page and javascript will attempt to rearrange it for you. Editing the comments.php, moving the tag, and uncheck the Comment Form Rearrange box on the Captcha options page is the best solution. Why is it better to uncheck the Comment Form Rearrange box and move the tag? Because the XHTML will no longer validate if it is checked. Why do I get "ERROR: Could not read CAPTCHA cookie. Make sure you have cookies enabled and not blocking in your web browser settings. Or another plugin is conflicting."? Check your web browser settings and make sure you are not blocking cookies for your blog domain. Cookies have to be enabled in your web browser and not blocked for the blog web domain. If you get this error, your browser is blocking cookies or you have another plugin that is conflicting (in that case I would like to help you further to determine which one). I can tell you that the plugin called "Shopp" is not compatible because it handles sessions differently causing the "ERROR: Could not read CAPTCHA cookie. Make sure you have cookies enabled". The Cookie Test can be used to test if your browser is accepting cookies from your site: Click on the "Test if your PHP installation will support the CAPTCHA" link on the Options page. or open this URL in your web browser to run the test: /wp-content/plugins/si-captcha-for-wordpress/captcha-secureimage/test/index.php Troubleshooting if the CAPTCHA form fields and image is not being shown: Do this as a test: Activate the SI CAPTCHA plugin and temporarily change your theme to the "Wordpress Default" theme. Does the captcha image show now? If it does then the theme you are using is the cause. Your theme must have a <?php do_action(comment_form, $post->ID); ?> tag inside your comments.php form. Most themes do. The best place to locate the tag is before the comment textarea, you may want to move it if it is below the comment textarea. This tag is exactly where the captcha image and captcha code entry will display on the form, so move the line to before the comment textarea, uncheck the Comment Form Rearrange box on the Captcha options page, and the problem should be fixed. Troubleshooting if the CAPTCHA image itself is not being shown: By default, the admin will not see the CAPTCHA. If you click "log out", go look and it will be there. If the image is broken and you have the CAPTCHA entry box: This can happen if a server has too low a default permission level on new folders. Check and make sure the permission on all the captcha-secureimage folders are set to permission: 755 all these folders need to be 755: - si-captcha-for-wordpress - captcha-secureimage - audio - gdfonts - images - test Here is a tutorial about file permissions This script can be used to test if your PHP installation will support the CAPTCHA: Click on the "Test if your PHP installation will support the CAPTCHA" link on the Options page. or open this URL in your web browser to run the test: /wp-content/plugins/si-captcha-for-wordpress/captcha-secureimage/test/index.php Is this plugin available in other languages? Yes. To use a translated version, you need to obtain or make the language file for it. At this point it would be useful to read Installing WordPress in Your Language from the Codex. You will need an .mo file for SI CAPTCHA that corresponds with the "WPLANG" setting in your wp-config.php file. Translations are listed below -- if a translation for your language is available, all you need to do is place it in the /wp-content/plugins/si-captcha-for-wordpress directory of your WordPress installation. If one is not available, and you also speak good English, please consider doing a translation yourself (see the next question). The following translations are included in the download zip file: Arabic (ar) - Translated by Amine Roukh Belorussian (by_BY) - Translated by Marcis Gasuns Danish (da_DK) - Translated by Parry French (fr_FR) - Translated by Pierre Sudarovich German (de_DE) - Translated by Sebastian Kreideweiss Greek (el) - Translated by Ioannis Italian (it_IT) - Translated by Gianni Diurno Norwegian (nb_NO) - Translated by Roger Sylte Polish (pl_PL) - Translated by Tomasz Portuguese Brazil (pt_BR) - Translated by [Newton Dan Faoro] Russian (ru_RU) - Translated by Neponyatka Spanish (en_ES) - Translated by LoPsT Swedish (sv_SE) - Translated by [Benct] Traditional Chinese, Taiwan Language (zh_TW) - Translated by [Cjh] Turkish (tr_TR) - Translated by Volkan More are needed... Please help translate. Are the CAPTCHA audio files available in other languages? Portuguese brazil (pt_BR) audio files are available. Wait until after you install the plugin. Download the audio files: Portuguese brazil (pt_BR) audio files download and follow instructions in the Readme.txt inside the zip file. Can I provide a translation? Of course! It will be very gratefully received. Use PoEdit, it makes translation easy. Please read Translating WordPress first for background information on translating. Then obtain the latest .pot file and translate it. * There are some strings with a space in front or end -- please make sure you remember the space! * When you have a translation ready, please send the .po and .mo files to wp-translation at 642weather dot com. * If you have any questions, feel free to email me also. Thanks! Is it possible to merge the translation files I sent to you with the ones of the newest version? If you use PoEdit to translate, it is easy to translate for a new version. You can open your current .po file, then select from the PoEdit menu: "Catalog" > "Update from POT file". Now all you have to change are the new language strings.

Author: Andrey Sorvin Smart invisible captcha for wordpress comments. This small plugin protects your blog from a spam in comments
Installation:
Upload invisible_captcha.php to the /wp-content/plugins/invisible_captcha/ directory Activate the plugin through the Plugins menu in WordPress The important remark: The Identifier of the button for comment sending in your comment-page should be "submit".