2005
09.16

Captcha! Plugin

Warning! CAPTCHA! is DISABLED on this site.
Even though this plugin is still maitained, I’m using another one. Read why.

You can also go to the phorum for help.

I wanted my WordPress to have one of those nice Captchas challenges to avoid spam.

There are already some of them, but I found them not suitable for my webhosting service (Secureimage), or a bit weak (Trencaspammer). So I started my own based on the HN Captcha PHP class. To see a demo of this plugin just try to enter a comment on the main page (Okay, still in Spanish. Bilingual web soon to come).

Needs the GD library class, a Javascript compatible browser and TrueType fonts in a server folder to work. You can download some of TTF (TrueType) fonts for free from Dafont. The more artistic the font, the better the challenge will be.
The plugin allows to request another challenge if the current one is illegible.

Hope you enjoy it.

[Download] Current version of Captcha! plugin

Changelog:

  • Version 2.6
    Bugfix: Fixed a security bug against CSRF and XSS
    Bugfix: Prevents the code length to be lower than one char.
  • Version 2.5d
    +Feature: Enhaced GDLib version detection (does not require phpinfo() function).
  • Version 2.5c
    Bugfix: Fixed a bug which prevented some effect options (sinewave, B&W) to be updated correctly. Thanks Hugo!.
  • Version 2.5b
    Bugfix: Fixing bad javascript rendering bug. Thanks, Gidion!.
  • Version 2.5a
    Bugfix: Stupid bug. Captcha 2.5 was allowing comments. Grrrr.
  • Version 2.5
    Bugfix: Captcha 2.x seemed to be filtering pingbacks. Fixed.
  • Version 2.4
    Feature: Checks for the availability of ImageFilter function (PHP >= 5.0)
    Feature: Checks for the availability of Iconv.
  • Version 2.3
    Feature: Added Anchor so every try the page jumps directly to captcha input.
    Feature: Cleaner code.
    Feature: Sine wave color-flag (optional), only color and Black & White optional mode.
    Feature: Can choose number of max tries.
  • Version 2.2
    Bugfix: Captcha didn’t delete spam comments in WP 1.5. Fixed.
  • Version 2.1
    Bugfix: Fixed a bug in the refresh button.
    Feature: Added senoidal image distortion.
    Feature: Deletes guessed keys.
  • Version 2.0
    Feature: Danish translation of captcha! (Thanks, Ulrik Nielsen)
    Feature: Portuguese (Brazil) translation of captcha! (Thanks, Francis Augusto Medeiros)
    Feature: One single file! Captcha is now one single compact file. Source code is much cleaner and neat (for future versions, however, CSS and languaje files will be apart).
    Feature: Images generated on the fly. TMP/ cache images no longer needed (and no more “Garbage error”
    Feature: Now Captcha! remembers previous state, so a user is given several tries (3 by default) to guess it before changing to a new code. The code look is different each time, even if the same code is required (improved security).
    Feature: Improved security. Real public key not shown, so it makes really difficult to guess the sequence via a bot.
    Feature: Random pattern background and code colors added => Greater security.
    Feature: Annoying javascript popup (when bad code entered) has been removed: Now the user will be asked to reenter the code in the captcha form.
    Bugfix: Some servers have permalinks broken, so entering a bad captcha returned to the main page, losing comment content. This should be fixed now.

See Changelog for previous versions ▼

Some sites using (or which used ;)) this captcha:

[Uniform Server] [stefanrusche.de] [A Dose of Geekish Sanity] [Markus’ Blog] [Silke Thoss] [scudly.com] [AAWakenings] [bdk… the man, the myth, the whatever…] [ElectroLund] [Pedja] [Outlandish Josh] [macslow.mine.nu] [Zoomer v2.0] [The BullPen Blog] [me blog] [Natalie Gulbis – Sport Memorabilia] [Bitte keine heiße Asche einwerfen] [Daniel Lemire’s blog] [Ido’s Blog] [Onderonsjes] [schimana.net] [Hillsidelounge] [MLL’s web site] [Axel Segebrecht] [Normadicoder] [Laitsas’ Penguinblog]

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  1. […] Captcha!: Muestra una imagen distorsionada (’captcha’) con un código alfanumérico que el usuario debe introducir para que su comentario sea aceptado (se usa contra el Spam). […]

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  2. […] Aparte de Captcha!, para luchar contra el SPAM via trackbacks, uso Trackback Validator, que funciona muy bien, pero tiene un problema.: independientemente de que el Trackback sea basura o no, lo recibo por correo si activo “enviar comentarios por correo” en el panel de administración. […]

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  3. […] While there are a couple of other great plugins that are similar like Meyerweb’s WP-Gatekeeper ,  Did You PASS Math?, ΛορδΧηαος’s Challenge Plugin and Captcha!, I am a real fan of the simplicity, functionality and currentness of Peter’s Custom Anti-Spam Plugin. Peter’s plugin works with WordPress 2.1.2 and has some great functionality that includes customizing the words used for detecting spam still allows for pingbacks and trackbacks! Something I certainly still want and I know you do too! […]

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  4. […] Ui, ja, guckmal hier: http://www.boriel.com/?page_id=17 […]

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  5. […] Для тех кому понадобится качнуть плагин можно отсюда, там же и шрифты под неё. […]

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  6. […] Kyseinen Captcha!-plugini perustuu HN Captcha-PHP-luokkaan. […]

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  7. […] Captcha! […]

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  8. […] My own WordPress blog here had been plagued by spambots for over a week mainly because the hosting providers didn’t have any anti-spam plugin available. So in my searches I came across Captcha, which does the trick. Captcha is one of little graphics that we commonly see on sites to verify that the user is a human and not some form of automated tool. […]

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  9. […] And if you decide to try and leave a comment, you will be presented with an image asking you to fill in the box with some letters and numbers. I’m sure you’ve all seen this before and I apologize that my laziness is causing you more work. If you’re interested in getting something similar, you can download it for yourself at http://www.boriel.com/?page_id=17 it will probably break in the future. But if you’re interested it is still available. […]

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  10. […] CaptCha! http://www.boriel.com/?page_id=17 […]

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  11. […] Captcha! – Cria uma imagem com texto, gerado aleatoriamente, que os visitantes tm de inserir […]

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  12. […] Captcha!最為花俏、美觀的 CAPTCHA Plug-In,安裝時也需設定好字型支援。樣本圖片: […]

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  13. […] your own fonts to use with the plugin so you can be really dynamic in how the image turns out.                     Tags:  NoTags […]

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  14. […] Så hvis du fremover skulle finde en grund til at skirve en kommentar i min blog – hvilket du er meget velkommen til – så skal du lige genkende 5 tal og/eller bogstaver, der er blevet forvredent lidt. Systemet hedder Captcha! […]

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  15. […] Tonight I did a whole bunch of stuff to my weblog.  It all started because I wanted to install the Now Reading plugin that I read about on Something Awful, so I could do all sorts of cool book stuff on here.  It recommended installing WordPress Widgets.  When I installed that I got a script error, and decided to go ahead and upgrade to WordPress 2.1.  In the process I upgraded the Captcha plugin I’m using and had to modify my custom theme for Widgets.  I ended up cleaning up the CSS a lot in the meantime.  Now I just need some gradients or something.  After I got Now Reading up and running I started poking around the Widgets plugin site and found some nifty widgets like this APOD Widget and a Gallery 2 widget.  Wait, what’s that, there’s a way to integrate Gallery and WordPress?  Oh man I have been wondering about this for a while but never really looked for anything like it.  So I installed WPG2 and enabled the Random Image widget. […]

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  16. […] Since I decided to start blogging again on this blog, I saw my WordPress Captcha plugin from Boriel didn’t work anymore. […]

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  17. […] Captcha! (http://www.boriel.com/?page_id=17)  […]

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  18. […] Final note, hopefully, on the comment spam and trackback issue — I found a different bot check software called Captcha! that still provides the security of random image generation to prove human commenting but that also allows continued trackback capability. Non-registered users will have to type in the code at the bottom of the comment field before submitting, where registered users will not need to verify their comments. Oh, and let me know if you find the font too difficult to read because that’s an option I can change. Enough of this….Share This Tags: plugins, software, spam, trackback, wordpressplugins, software, spam, trackback, wordpress […]

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  19. […] Hier klicken […]

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  20. […] 我查了一下Captcha的原作者, http://www.boriel.com/?page_id=17 他說他改用了另外一套防止spam的軟體 wp-hashcash, 這邊他有提到 為什麼? 總之我看完以後我也改用了, 實驗看看吧, 技術上我還在瞭解其原理: What it does: […]

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  21. […] Captcha!: Muestra una imagen distorsionada (’captcha’) con un código alfanumérico que el usuario debe introducir para que su comentario sea aceptado (se usa contra el Spam). […]

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  22. […] Kapcsa By JoeP A spam elleni harc jegyében megint kavartam a blogon. Az Akismet lehet, hogy jó, de nekem decemberben napi 30-40 spam-et engedett át – és hiába fogott meg mellette százat, hagyott azért munkát nekem is. Ekkor jött a Hashcash, mely az Akismet-tel párban abszolút remekül dolgozott. A Hashcash olyan napi 10 szemetet engedett át, azokat meg az Akismet csípte nyakon. A védelmen egy hónap alatt olyan 3 spam jutott át. A gond csak az, hogy ehhez bekapcsolt javascript kellett a látogató részéről – és némi szerencse. Eddig kétszer fordult elő ugyanis olyan anomália, hogy valakinek a kommentje ‘elveszett’ az éterben: az illető elküldte, a WordPress tudomásul vette, a blogon meg is jelent, hogy van komment az íráshoz – de az mégsem érkezett be az adatbázisba. Emiatt úgy döntöttem, hogy szép az, ami egyszerű: kikapcsoltam mindkét védelmet és feltelepítettem egy Captcha! plugint, dacára annak, hogy a szerzője mindenáron megpróbált lebeszélni róla. Mostantól itt is be kell gépelni azt az öt karaktert, melyet meglehetősen meggyötörve tesz ki egy grafikára a plugin. […]

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  23. […] 到最後,決定了用 Captcha! plugin。雖然花了一點點時間在設定上,但最起碼是能夠用了,不像之前的,花多少時間和它摶鬥都不夠。 2005-12-23 02:37 […]

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  24. […] Jeg har også fået gjort noget ved mine plugins, jeg har fx smidt SimplePie pluginet(tidligere indlæg) ud igen og begyndt arbejdet på mit eget. Har skiftet Captcha pluginet ud med Akismet, og det var en klar forbedring! Resten af mine aktive plugins er Hello Dolly og WordPress Database Backup, men de er vidst nok begge standart plugins. […]

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  25. […] Finally, I choose Captcha! since it is easy to install and my web host has GDlib pre-installed. In order for the plugin to work, one needs to download some twisted TTF fonts freely available from this site. Share and Enjoy: […]

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  26. […] CaptCha! […]

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  27. […] Captcha! is a more direct approach. Rather than guessing whether a comment is legit or not, why not just block out the generally irritating spambots before they can comment at all? […]

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  28. […] Wednesday, December 13, 2006 @ 5:54 pm Posted in: Technology I installed the Captcha! plugin for WordPress the other day. So far, so good as far as not getting any more spam comments. However, I want to make sure that people aren’t having problems commenting — so please comment on this entry and let me know if it works for you.  captcha, plugins, wordpress Leave a Reply […]

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  29. […] Da dieses ach so tolle Ajax-Spam-Schutz-Script nicht funktioniert (grade flatterte mal wieder eine neue Mail rein) werde ich wohl ein Captcha nehmen. Dabei ist meine Wahl auf CaptCha! gefallen – vielleicht taugt das ja was :-/ […]

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  30. […] Liebe Gemeinde, ein Captcha-Plugin, das die manuelle Eingabe eines visuell dargestellten Zufallscodes beim Kommentieren erfordert, erfüllt den gleichen Zweck! Es schützt sehr zuverlässig vor Spambots ohne die lokale Datenbank damit zu belasten. Und User denen das Abtippen des Captcha-Codes jedesmal zu viel abverlangt ist, die dürfen sich auch gerne einen Account registrieren und können als verifizierter User der Prüfung entgehen. […]

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  31. […] … musste ich das Eintragen eines Kommentars in mein blog durch Captcha! sichern. Vor lauter spam war kein echtes Kommentar mehr zu identifizieren. Ich hoffe das reicht vorerst als Abwehrmassname, um den ganzen ein wenig den Riegel vorzuschieben! […]

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  32. […] http://www.boriel.com/?page_id=17 […]

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  33. […] Als Captcha bezeichnet man die grafischen Texte, die zur Überprüfung in ein Eingabefeld eingetragen werden müssen. Typischerweise handelt es sich um ein Bild das aus verschiedenen Buchstaben und Ziffern besteht. Um automatisierte Spambots von menschlichen Benutzern unterscheiden zu können, muss der betreffende Texte entziffert und eingegeben werden. Für WordPress existieren diverse Captcha-Plugins – einfach zu installieren ist captcha!, der Autor selbst empfiehlt allerdings die Verwendung von HashCash (siehe unten). […]

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  34. […] 但是?怎麼?測此次 comment_post 是?為 trackback/pingback 呢?我?是 wordpress ?人,所以?好?看一下 Captcha! 的程?碼,原來關?在於,也註冊 pingback_post 與 trackback_post 這兩個 actions,於處?此兩個 actions 時記錄於 $this->is_trackback,然後在處? comment_post 時,若是 $this->is_trackback 的話,就直接通?。 […]

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  35. […] Pagi ini saya ditanya teman tentang cara paling efektif menangkal spam pada WordPress. Plugins yang sekarang saya gunakan adalah Akismet dan Captcha. Menggunakan kedua plugins tersebut memang sangat nyaman sekali. Saya tidak perlu me-moderate comment yang masuk. Semua yang tidak lolos dari saringan masuk (input code yang di generate oleh captcha) akan langung di delete. Ini termasuk pada comment dalam bentuk pinback dan trackback. Disinilah salah satu kelemahan Captcha, meski bagus dalam menangani spam comment, tetapi buruk dalam menangani pingback dan trackback. Captcha tidak dilengkapi dengan pingback dan trackback validator untuk membedakan pingback dan trackback spam. Saya sudah mencoba menginstal plugins trackback validator untuk mem-validasi pingback dan trackback, tetapi nampaknya hasilnya tidak sesuai dengan yang diharapkan. […]

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  36. […] This will help for others to search out tag words to find your blog postings with search engines such as Google, Yahoo, Technorati and Feedburner. Now the one plugin that I cannot do without is the Captcha! spam blocker. I loath spam and I was really annoyed when I used to have to clear out the spam comments. This plugin cut that out. It’s still available however, this will no longer be maintained by the author as he has moved on to using the WordPress HashCash plugin. I haven’t tried this one myself but, I have heard good reviews so I’ll put that on my list of things to do (…number 28,735). […]

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  37. […] Update: I added an image authentication plug-in. The plug-in is called captcha!, and to make it less hard for you. All you have to do is authenticate ONE character from the image… […]

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  38. […] Debido a la gran cantidad de robots spammers que se dedican a mandar spam a los blogs en forma de comentarios he decidido insertar un reto de inteligencia artificial (módulo Captcha) a la hora de insertar comentarios de forma que las máquinas no superen el reto y un humano lo haga facilmente. […]

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  39. […] Da wir in letzter Zeit von Comment Spam überrollt werden (>10.000 Messages in ~6Monaten), hab ich eben mal ein Captcha Plugin installiert. Hoffe das bereitet nicht mehr Probleme als es lösen sollte […]

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  40. [English] To ALL Users: Comments are closed. A new forum (phpBB2) has been opened for support and questions. Please, go to http://www.boriel.com/phpbb2/

    [Español] A TODOS los usuarios: Los comentarios se han cerrado. Se ha abierto un nuevo foro (phpBB2), para preguntas y ayuda. Por favor, diríjanse a http://www.boriel.com/phpbb2/

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  41. Hi, I need some help with your plug !!!

    I think that is my theme that is not compatible because don’t have the usually comment.php file but only a index.php file that make it all.

    there’s any string of code to add whenever any theme is not compatible with your plug ??

    please help me if possible thanks !

    Because the same plug ( your ) work perfectly with other themes…. but i wish this one !

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  42. HI Thank you for publishing it.
    I cannot make it work.
    I get this:
    Error! No TTF font found!
    Warning: Cannot modify header information – headers already sent by (output started at /content/web/webmanual/wp-content/plugins/captcha.php:238) in /content/web/webmanual/wp-includes/pluggable-functions.php on line 272

    Any Ideas?
    Thank you in advance!

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  43. Excellent work!

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  44. 😯 😕

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  45. Hi,

    Great plugin!

    I recently wrote a CAPTCHA that requires no image library – it uses ASCII Art Fonts!

    you can see an online example here

    Thanks for a great plugin!

    – Tim

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  46. Testing

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  47. cool plugin

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  48. Hi, thanks for your information. Great site.

    Keep it real…

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  49. Hey Boriel!

    Keep up the great work, I know this is a hobby, so if i had the cash I would send it your way, but I don’t so instead I am sending you this comment to say “I don’t have any errors” Just saying thanks and keep up the great work… when you have the time! 🙂

    Take care
    David

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