Few technologies have ever been so disliked by both those who enforce its use and those upon whom its use has been enforced — yet so widely adopted as captcha.
With the spam flood at the website gates, and no viable alternatives anywhere in sight, webmasters are simply left without a choice — and millions of captchas are being solved every day.
Whether you like it or not — welcome to the world of CAPTCHA.
Q: So, what goes into this captcha directory?
A: According to its name the captchas will be an easy answer.
Q: But what a captcha is? How is it defined for the purpose of this directory?
A: If there is something that users have to solve... — it will satisfy a captcha definition.
Q: So, all captcha-enabled form processing and CMS software also qualifies?
A: No, packaging is also a factor. It must be stand-alone captcha software or captcha service built with the purpose of being embedded into something else.
Q: Anything else?
A: Captcha breakers and captcha alternatives are also welcome.
Q: What fits within a captcha software description? Distorted text type captchas only, or there is room for other types as well?
A: It is open to all non-trivial types of captcha software.
Q: What about new conceptual captchas with less then perfect software implementations?
A: Even for them. If the concept is interesting and theoretically provides a reasonable level of protection, it can find its place here.
| Version | 2.0 |
| Status | R.I.P. |
| Release Date | 2006-04-09 |
| Product Homepage | www.tipstricks.org |
| Online demo | www.tipstricks.org/example.asp |
| Software Licence | Common Public License |
| List price | Free |
| Free trial | Yes |
| Vendor | Emir Tüzül |
| Vendor homepage | Unknown |
| Captcha Algorithms | Unknown |
| Sound support | No |
| Reload button | No |
| Programming language | ASP |
| Source code available | Yes |
| Captcha type | Distorted Text |
| Product type | ASP CAPTCHA Script |
| OS support | Windows |
| 64-bit support | Unknown |
| Dependencies | Unknown |
| Inherited | N/A |
| IDE support | Unknown |
| Language APIs | ASP |
| CMS plugins | Unknown |
last updated on 2007/12/19 14:38
| Version | 2.0.9 |
| Status | Active |
| Release Date | 2009-02-12 |
| Product Homepage | captcha.biz/asp-captcha.html |
| Online demo | captcha.biz/demo/captcha_demo.aspx |
| Software Licence | Commercial |
| List price | Free, $59 - $499 |
| Free trial | Yes |
| Vendor | Lanapsoft, Inc |
| Vendor homepage | captcha.biz |
| Captcha Algorithms | 50 |
| Sound support | Yes |
| Reload button | No |
| Programming language | C++ |
| Source code available | Yes |
| Captcha type | Distorted Text |
| Product type | COM CAPTCHA Component |
| OS support | Windows |
| 64-bit support | Yes |
| Dependencies | None |
| Inherited | N/A |
| IDE support | N/A |
| Language APIs | COM, ASP |
| CMS plugins | None |
last updated on 2009/09/14 21:15
| Version | 2.0.14 |
| Status | Active |
| Release Date | 2009-09-14 |
| Product Homepage | captcha.biz/asp.net-captcha.html |
| Online demo | captcha.biz/demo/captcha_demo.aspx |
| Software Licence | Commercial |
| List price | Free, $59 - $499 |
| Free trial | Yes |
| Vendor | Lanapsoft, Inc |
| Vendor homepage | captcha.biz |
| Captcha Algorithms | 50 |
| Sound support | Yes |
| Reload button | Yes |
| Programming language | C# |
| Source code available | Yes |
| Captcha type | Distorted Text |
| Product type | ASP.NET CAPTCHA Component |
| OS support | Windows |
| 64-bit support | Yes |
| Dependencies | .NET Framework |
| Inherited | |
| IDE support | Visual Studio 2003, Visual Studio 2005, Visual Studio 2008 |
| Language APIs | ASP.NET |
| CMS plugins | None |
last updated on 2009/09/14 21:17
| Version | 1.0 |
| Status | |
| Release Date | 2006-10-31 |
| Product Homepage | www.motobit.com/util/captcha |
| Online demo | www.motobit.com/util/captcha |
| Software Licence | |
| List price | Free |
| Free trial | Yes |
| Vendor | Motobit Software |
| Vendor homepage | www.motobit.com |
| Captcha Algorithms | |
| Sound support | No |
| Reload button | No |
| Programming language | VB Script |
| Source code available | Yes |
| Captcha type | Undistorted Text |
| Product type | ASP Captcha Script |
| OS support | Windows |
| 64-bit support | Unknown |
| Dependencies | OWC |
| Inherited | |
| IDE support | |
| Language APIs | |
| CMS plugins |
last updated on 2007/10/14 04:01
| Version | 1.01 |
| Status | |
| Release Date | 2004-02-02 |
| Product Homepage | www.codeproject.com/aspnet/captchaimage.asp |
| Online demo | Not Available |
| Software Licence | |
| List price | Free |
| Free trial | Yes |
| Vendor | BrainJar |
| Vendor homepage | www.brainjar.com |
| Captcha Algorithms | |
| Sound support | No |
| Reload button | No |
| Programming language | C# |
| Source code available | Yes |
| Captcha type | Distorted Text |
| Product type | C# Captcha Class |
| OS support | Windows |
| 64-bit support | Yes |
| Dependencies | .NET Framework |
| Inherited | |
| IDE support | |
| Language APIs | |
| CMS plugins |
last updated on 2007/10/14 03:57
| Version | 2.1 |
| Status | Active |
| Release Date | 2007-01-29 |
| Product Homepage | www.codeproject.com/aspnet/CaptchaControl.asp |
| Online demo | |
| Software Licence | |
| List price | Free |
| Free trial | Yes |
| Vendor | Jeff Atwood |
| Vendor homepage | www.codinghorror.com |
| Captcha Algorithms | |
| Sound support | No |
| Reload button | No |
| Programming language | VB.NET |
| Source code available | Yes |
| Captcha type | Distorted Text |
| Product type | ASP.NET Captcha Component |
| OS support | Windows |
| 64-bit support | Yes |
| Dependencies | .NET Framework |
| Inherited | |
| IDE support | |
| Language APIs | ASP.NET |
| CMS plugins |
last updated on 2007/10/20 13:42
| Version | 1.0 |
| Status | Active |
| Release Date | 2007-08-20 |
| Product Homepage | www.floresense.com/controls/dN/captcha/index.php |
| Online demo | |
| Software Licence | Commercial |
| List price | Free, $16 |
| Free trial | Yes |
| Vendor | Floresense Solutions |
| Vendor homepage | www.floresense.com |
| Captcha Algorithms | |
| Sound support | No |
| Reload button | No |
| Programming language | |
| Source code available | No |
| Captcha type | Distorted Text |
| Product type | ASP.NET CAPTCHA Control |
| OS support | Windows |
| 64-bit support | Unknown |
| Dependencies | .NET Framework 2.0 |
| Inherited | |
| IDE support | |
| Language APIs | |
| CMS plugins |
last updated on 2007/10/20 13:42
| Version | All versions |
| Status | R.I.P. |
| Release Date | |
| Product Homepage | |
| Online demo | |
| Software Licence | |
| List price | |
| Free trial | |
| Vendor | SafaByte, ComponentForge, XtraComponents |
| Vendor homepage | Ever-changing |
| Captcha Algorithms | |
| Sound support | |
| Reload button | |
| Programming language | |
| Source code available | |
| Captcha type | |
| Product type | |
| OS support | |
| 64-bit support | |
| Dependencies | |
| Inherited | |
| IDE support | |
| Language APIs | |
| CMS plugins |
last updated on 2010/04/13 12:30
NetXtreme/AspXtreme CAPTCHA is Lanapsoft's BotDetect ASP.NET CAPTCHA rip-off based on a decompiled BotDetect CAPTCHA source code. Unlike original, AspXtreme CAPTCHA lacks a few features that 'the vendor' couldn't figure out, and is enhanced with multiple bugs not present in the original version. Stay away from it.
More about this particular rip-off, as well as about numerous other rip-offs done by the same 'vendor' with an ever changing name/brand and URL you can find at http://cheated.by.safabyte.net/.
Some folks find weird ways for making money.
| Version | 1.0.0 |
| Status | |
| Release Date | Unknown |
| Product Homepage | www.textdisguise.com |
| Online demo | www.textdisguise.com/TextDisguise/Demo.aspx |
| Software Licence | Commercial |
| List price | Free, $49 - $159 |
| Free trial | Yes |
| Vendor | 27 Seconds, Inc. |
| Vendor homepage | www.27seconds.com |
| Captcha Algorithms | Unknown |
| Sound support | No |
| Reload button | No |
| Programming language | VB.NET |
| Source code available | Yes |
| Captcha type | Distorted Text |
| Product type | .NET CAPTCHA Component |
| OS support | Windows |
| 64-bit support | Yes |
| Dependencies | .Net Framework |
| Inherited | N/A |
| IDE support | Unknown |
| Language APIs | .NET |
| CMS plugins | None |
last updated on 2007/10/11 00:45
| Version | 0.1 |
| Status | |
| Release Date | 2005-06-07 |
| Product Homepage | www.planet-source-code.com/vb/scripts/ShowCode.asp ?txtCodeId=9204&lngWId=4 |
| Online demo | Not Available |
| Software Licence | GPL |
| List price | Free |
| Free trial | Yes |
| Vendor | CS Shyam Sundar |
| Vendor homepage | csshyamsundar.wordpress.com |
| Captcha Algorithms | Unknown |
| Sound support | No |
| Reload button | No |
| Programming language | ASP, VBScript |
| Source code available | Yes |
| Captcha type | Distorted Text |
| Product type | ASP CAPTCHA Script |
| OS support | Windows |
| 64-bit support | Unknown |
| Dependencies | GD by Thomas Boutell., GD is copyright 2005 Boutell.com, Inc. ActiveX Wrapper For GD by Trevor Herselman |
| Inherited | None |
| IDE support | None |
| Language APIs | ASP |
| CMS plugins | None |
last updated on 2007/10/10 23:43
| Version | Unknown |
| Status | |
| Release Date | 2005-07-01 |
| Product Homepage | www.u229.no/stuff/Captcha |
| Online demo | www.u229.no/stuff/Captcha |
| Software Licence | Unknown |
| List price | Free |
| Free trial | Yes |
| Vendor | u229.no |
| Vendor homepage | www.u229.no |
| Captcha Algorithms | Unknown |
| Sound support | No |
| Reload button | No |
| Programming language | ASP, CSS, JavaScript |
| Source code available | Yes |
| Captcha type | Simple Question |
| Product type | ASP CAPTCHA Script |
| OS support | Windows |
| 64-bit support | Unknown |
| Dependencies | Unknown |
| Inherited | N/A |
| IDE support | Unknown |
| Language APIs | ASP |
| CMS plugins | Unknown |
last updated on 2007/10/10 23:43
| Version | 3.0 |
| Status | |
| Release Date | 2007-07-22 |
| Product Homepage | www.webwizcaptcha.com |
| Online demo | www.webwizguide.com/webwizcaptcha/demo |
| Software Licence | Commercial |
| List price | Free, $15 - $100 |
| Free trial | Yes |
| Vendor | Web Wiz |
| Vendor homepage | |
| Captcha Algorithms | Unknown |
| Sound support | No |
| Reload button | Yes |
| Programming language | ASP |
| Source code available | Unknown |
| Captcha type | Distorted Text |
| Product type | ASP CAPTCHA Component |
| OS support | Windows |
| 64-bit support | Unknown |
| Dependencies | |
| Inherited | N/A |
| IDE support | |
| Language APIs | ASP |
| CMS plugins |
last updated on 2007/10/11 01:58
Q: What is a captcha service? How is it defined for the purpose of this directory?
A: If the task users have to solve is generated and in the real-time delivered to the requesting user or website by a third-party... — it will satisfy a captcha service definition.
Q: What about packaging?
A: Same as anywhere else within directory — only stand-alone captcha services built with the purpose of being embedded into something else. No form-processing services, please.
| Version | N/A |
| Status | Active |
| Release Date | 2008-10-09 |
| Product Homepage | www.captcha.cc |
| Online demo | Yes |
| Software Licence | N/A |
| List price | Free |
| Free trial | Yes |
| Vendor | Document Root, Inc. |
| Vendor homepage | www.documentroot.com |
| Captcha Algorithms | N/A |
| Sound support | Yes |
| Reload button | Yes |
| Programming language | Perl |
| Source code available | No |
| Captcha type | Distorted Text |
| Product type | CAPTCHA Service |
| OS support | N/A |
| 64-bit support | N/A |
| Dependencies | N/A |
| Inherited | N/A |
| IDE support | Unknown |
| Language APIs | ASP, Python, PHP, ColdFusion, Perl, Java, Ruby |
| CMS plugins | None supplied |
last updated on 2009/06/04 10:39
| Version | Unknown |
| Status | |
| Release Date | Unknown |
| Product Homepage | captchas.net |
| Online demo | No |
| Software Licence | N/A |
| List price | Free, $160/year |
| Free trial | Yes |
| Vendor | Felix Holderied & Sebastian Wilhelmi |
| Vendor homepage | holderied.de, seppi.de/index.html.en |
| Captcha Algorithms | Unknown |
| Sound support | Yes |
| Reload button | No |
| Programming language | Unknown |
| Source code available | No |
| Captcha type | Distorted Text |
| Product type | CAPTCHA Service |
| OS support | N/A |
| 64-bit support | N/A |
| Dependencies | N/A |
| Inherited | N/A |
| IDE support | None |
| Language APIs | N/A |
| CMS plugins | Plone |
last updated on 2007/10/11 02:06
| Version | N/A |
| Status | |
| Release Date | Unknown |
| Product Homepage | www.recaptcha.com |
| Online demo | recaptcha.net/learnmore.html |
| Software Licence | N/A |
| List price | Free |
| Free trial | Yes |
| Vendor | Carnegie Mellon University |
| Vendor homepage | www.cmu.edu |
| Captcha Algorithms | Unknown |
| Sound support | Yes |
| Reload button | Yes |
| Programming language | Python |
| Source code available | Unknown |
| Captcha type | Distorted Text |
| Product type | CAPTCHA Service |
| OS support | N/A |
| 64-bit support | N/A |
| Dependencies | N/A |
| Inherited | N/A |
| IDE support | Unknown |
| Language APIs | PHP, Python, Perl, Ruby, Java, ColdFusion |
| CMS plugins | WordPress, MediaWiki, phpBB, Movable Type, Drupal, Symphony, Typo3, NucleusCMS, vBulletin, Joomla |
last updated on 2007/10/14 04:03
| Version | |
| Status | |
| Release Date | Unknown |
| Product Homepage | www.spamerator.com |
| Online demo | None |
| Software Licence | N/A |
| List price | Free |
| Free trial | N/A |
| Vendor | |
| Vendor homepage | |
| Captcha Algorithms | |
| Sound support | No |
| Reload button | No |
| Programming language | |
| Source code available | N/A |
| Captcha type | Undistorted Text |
| Product type | CAPTCHA Service |
| OS support | N/A |
| 64-bit support | N/A |
| Dependencies | N/A |
| Inherited | N/A |
| IDE support | N/A |
| Language APIs | PHP |
| CMS plugins | None |
last updated on 2007/10/14 04:01
| Version | 1.0.0 |
| Status | |
| Release Date | Unknown |
| Product Homepage | www.textdisguise.com |
| Online demo | www.textdisguise.com/TextDisguise/Demo.aspx |
| Software Licence | N/A |
| List price | Free |
| Free trial | Yes |
| Vendor | 27 Seconds, Inc. |
| Vendor homepage | www.27seconds.com |
| Captcha Algorithms | Unknown |
| Sound support | No |
| Reload button | No |
| Programming language | VB.NET |
| Source code available | No |
| Captcha type | Distorted Text |
| Product type | SOAP CAPTCHA Service |
| OS support | N/A |
| 64-bit support | N/A |
| Dependencies | N/A |
| Inherited | N/A |
| IDE support | Unknown |
| Language APIs | SOAP API |
| CMS plugins | None |
last updated on 2007/10/11 00:46
Q: If this is a captcha directory, why are captcha breakers allowed at all?
A: Because one who is in the process of making a decision to deploy a captcha needs to know about the current state of captcha breaking solutions — and then later to periodically re-asses its standing against them.
Q: What types of "captcha breakers" one can expect to see here?
A: Various types of captcha breaking research articles, software, services (even human based ones), etc.
| Version | |
| Status | Inactive |
| Release Date | 2005-01-30 |
| Product Homepage | www.brains-n-brawn.com/aicaptcha |
| Online demo | No |
| Software Licence | |
| List price | |
| Free trial | No |
| Vendor | Casey Chesnut |
| Vendor homepage | www.brains-n-brawn.com |
| Captcha Algorithms | N/A |
| Sound support | N/A |
| Reload button | N/A |
| Programming language | |
| Source code available | No |
| Captcha type | Captcha Breaker |
| Product type | Comment Spam Bot |
| OS support | |
| 64-bit support | N/A |
| Dependencies | |
| Inherited | |
| IDE support | |
| Language APIs | |
| CMS plugins |
last updated on 2007/11/16 10:59
aiCaptcha is an excellent and easy to read article that includes a step by step guide on breaking of a particular weak captcha with some serious stuff — but without any rocket science involved in the process. And exactly because of that lack of rocket science aiCaptcha is a must read for anyone thinking about deploying captchas.
Even if you are not going to understand just about everything that is written in the article, aiCaptcha will make you able to recognize a lot of weaknesses in algorithms of many captchas that are available on the market today. In turn, you will be able to avoid deploying those weak captchas on your website.
aiCaptcha source code and executables are not available to the public.
| Version | |
| Status | Unknown |
| Release Date | Unknown |
| Product Homepage | www.captchakiller.com |
| Online demo | |
| Software Licence | |
| List price | |
| Free trial | Yes |
| Vendor | |
| Vendor homepage | www.captchakiller.com |
| Captcha Algorithms | N/A |
| Sound support | N/A |
| Reload button | N/A |
| Programming language | |
| Source code available | No |
| Captcha type | Captcha Breaker |
| Product type | RESTfull CAPTCHA Breaking Service |
| OS support | |
| 64-bit support | N/A |
| Dependencies | |
| Inherited | |
| IDE support | |
| Language APIs | |
| CMS plugins |
last updated on 2007/11/17 04:41
The long-term status of Captcha Killer is a bit unclear at this moment.
While the CaptchaKiller website does not state anywhere that the Captcha Killer is, or will be, out of business — the guy's post made 2007/09/24 clearly states:
"I'm facing legal trouble in the US. Can someone please help me move this company offshore? Any tips? Who should I be talking to?"
It seems that Captcha Killer got at least the MySpace legal team on its back and is now thinking about relocation. According to another post, the most likely destination is Panama.
Unfortunately, Captcha Killer says nothing about their captcha breaking technology :(
| Version | |
| Status | R.I.P. |
| Release Date | Unknown |
| Product Homepage | URL used to be: www.captchasolver.com |
| Online demo | |
| Software Licence | |
| List price | |
| Free trial | N/A |
| Vendor | |
| Vendor homepage | URL used to be: www.captchasolver.com |
| Captcha Algorithms | |
| Sound support | N/A |
| Reload button | N/A |
| Programming language | |
| Source code available | No |
| Captcha type | Captcha Breaker |
| Product type | Captcha breaking sweat-shop with Web Service API |
| OS support | |
| 64-bit support | N/A |
| Dependencies | |
| Inherited | |
| IDE support | |
| Language APIs | |
| CMS plugins |
last updated on 2007/12/22 06:32
CaptchaSolver seems not to exist any more. The website is down, and we do not think that we are going to hear about it again. At present, it is listed here only because of historical reasons.
CaptchaSolver used to be captcha-breaking sweat-shop. Numerous download sites still list CaptchaSolver API among their entries — but the download links lead to nowhere.
Hopefully, there will be someone out there who still has a copy of CaptchaSolver API. And if he/she is willing to forward it to captcha.org editors — in the future the CaptchaSolver entry might also get some educational reasons for its existence, beside the historical ones.
| Version | |
| Status | |
| Release Date | Unknown |
| Product Homepage | URL is: google27.com/index.php?option=com_content& task=view&id=1&Itemid=9 |
| Online demo | |
| Software Licence | |
| List price | |
| Free trial | No |
| Vendor | Google27 Solution |
| Vendor homepage | URL is: google27.com |
| Captcha Algorithms | |
| Sound support | N/A |
| Reload button | N/A |
| Programming language | |
| Source code available | No |
| Captcha type | Captcha Breaker |
| Product type | Captcha-breaking sweat-shop |
| OS support | |
| 64-bit support | N/A |
| Dependencies | |
| Inherited | |
| IDE support | |
| Language APIs | |
| CMS plugins |
last updated on 2007/12/22 06:34
Google27 is just another of those shady captcha-breaking sweat-shop entities that claim to provide the dark-side with a technology and low-cost labor needed for bypassing captchas on high-value-target websites such are MySpace and Yahoo.
Google27 claims they will do, as a professional service, all the integration work between your existing bot software and their captcha-entry agents.
Google27 website seems to be banned from Google index so we are not providing a direct link to it. Use copy/paste instead. We simply do not want to take the risk and make Google algorithms nervous about our site as well. Ironically, it seems that Google does not ban Google27 from AdWords :)
| Version | Unknown |
| Status | |
| Release Date | Unknown |
| Product Homepage | sam.zoy.org/pwntcha |
| Online demo | No |
| Software Licence | Unknown |
| List price | N/A |
| Free trial | No |
| Vendor | Sam Hocevar |
| Vendor homepage | sam.zoy.org |
| Captcha Algorithms | N/A |
| Sound support | N/A |
| Reload button | N/A |
| Programming language | Unknown |
| Source code available | No |
| Captcha type | Captcha Breaker |
| Product type | Non-CAPTCHA Library |
| OS support | Unknown |
| 64-bit support | Unknown |
| Dependencies | Unknown |
| Inherited | |
| IDE support | Unknown |
| Language APIs | Unknown |
| CMS plugins | N/A |
last updated on 2007/11/17 05:07
According to the PWNTCHA website PWNTCHA is 'simply a toolkit of image manipulation functions, and a list of known CAPTCHAs with the associated list of image operations to apply in order to decode each of them.'
So far we were unable to find the specifications of the PWNTCHA "toolkit". Also, we were unable to find PWNTCHA's "associated list of image operations to apply in order to decode each of them." Maybe we were looking on all the wrong places. Who knows.
If we were able to find those missing parts we would recommend PWNTCHA as a something that one interested in captchas should read. This way, there is really nothing to recommend.
PWNTCHA source code and executables are also not available to the public.
Q: If this is a captcha directory, why are captcha alternatives allowed at all?
A: Because there are some usage scenarios where a captcha alternative may solve at least a part of the same problems that captchas do.
Q: What types of captcha alternatives one can expect to see here?
A: For the time being it is only content-inspection type, with more types to follow on later.
Q: What about packaging?
A: Same as anywhere else within this directory, only stand-alone software or services built with the purpose of being embedded into something else.
| Version | N/A |
| Status | |
| Release Date | Unknown |
| Product Homepage | akismet.com |
| Online demo | N/A |
| Software Licence | N/A |
| List price | Free, $5 - $750+/month |
| Free trial | Yes |
| Vendor | Automattic, Inc. |
| Vendor homepage | automattic.com |
| Captcha Algorithms | N/A |
| Sound support | N/A |
| Reload button | N/A |
| Programming language | Unknown |
| Source code available | No |
| Captcha type | Alternative Technology |
| Product type | Non-CAPTCHA Service |
| OS support | N/A |
| 64-bit support | N/A |
| Dependencies | N/A |
| Inherited | N/A |
| IDE support | Unknown |
| Language APIs | Python, PHP, ColdFusion, Perl, Java, Ruby, Ruby on Rails, Lasso, .NET |
| CMS plugins | Movable Type, Drupal, phpBB, Blojsom, Bloxsom, Geeklog, Serendiptity, Nucleus, b2evolution, WordPress, PunBB, Expression Engine, Coppermine, Lifetype, Simple Machine Forums, Phorum, tDiary, MyBulletinBoard, PostNuke, Joomla, EZ Publish |
last updated on 2007/11/09 21:38
Akismet might be an interesting captcha alternative for those folks to whom comment spam is the only problem caused by bots.
Technologically, Akismet is based on some form of automated spam-filtering. The self-correction of algorithms is made possible by the feedback that is constantly flowing-in through the built-in collaborative component.
If you are member of the above-mentioned group, and the web side of your business can survive some false positives and negatives that will inevitably keep happening forever as a result of Akismet's technological foundation, it might be worth to give Akismet a try.
While Akismet will not solve your spam problems, it will make living with them much easier.
| Version | 1.1 |
| Status | Active |
| Release Date | 2007-11-07 |
| Product Homepage | defensio.com |
| Online demo | |
| Software Licence | |
| List price | Free, $5 - $50+/month |
| Free trial | Yes |
| Vendor | Karabunga, Inc. |
| Vendor homepage | karabunga.com |
| Captcha Algorithms | |
| Sound support | N/A |
| Reload button | N/A |
| Programming language | |
| Source code available | No |
| Captcha type | Alternative Technology |
| Product type | Non-CAPTCHA Service |
| OS support | |
| 64-bit support | N/A |
| Dependencies | |
| Inherited | |
| IDE support | |
| Language APIs | Ruby on Rails, .NET, Java, PHP |
| CMS plugins | WordPress, PixelPost |
last updated on 2007/11/09 21:36
The word CAPTCHA is an acronym for "Completely Automated Public Turing test to tell Computers and Humans Apart."
Synonym wanna-be terms for captcha are numerous and nowhere even close of being in as widespread use. Some of those are Security Image Generator (SIG), Human Verification Test (HVT), and Human Interaction Proof (HIP), with the last one being favored by Microsoft.
More often captchas are simply incorrectly refered as security image, security code, security image code, turing test, reverse turing test, validation image, validation image code, image validation, verification image, verification image code, image verification, etc. While these terms when stretched may indeed describe a captcha they are primarily used as names for some other completely unrelated things.
Common misspellings for captcha are capatcha, captsha, capttcha, chaptcha, etc. together with their plural forms.
Few excerpts from the future captcha.org User Manual:
Captcha History:
If we put aside work done by Alan Turing in the 1950s, the first discussion of automated tests which distinguish humans from computers for the purpose of controlling access to web services is in the 1996 manuscript "Verification of a human in the loop, or Identification via the Turing Test" written by Moni Naor from the Weizmann Institute of Science.
For the information on what happened after that we suggest you to do the same thing that we do — stay tuned to the ever-changing 'origin' section of the captcha article on Wikipedia :)