Contrived acronym in computer science and web development: Captcha

The term “captcha” was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas Hopper and John Langford of Carnegie Mellon University to denote a webpage element that is designed to tell humans and robots automatically apart: Captcha stands for Completely Automated Public Turing test to tell Computers and Humans Apart [1]. A captcha image, consisting of randomly generated characters squiggling inside a rectangle, is often encountered as a required-to-do field within a submit form. Misrecognizing certain letters or symbols, a user may get the interrogation vibe when asked if she would mind to do it again (and again …). In a recent TechnoFile contribution, David Pogue highlights the functioning of captchas as efficiency barriers and suggests the following meaning: Computers Annoying People with Time-wasting Challenges that Howl for Alternatives [2].

In case you haven't found an alternative yet or are going to argue that captchas are nevertheless pretty good in capturing—or should I write captcharing—machines employed by misconducting humans, then some interesting websites and JavaScript code will be helpful. Client side as well as server side scripting has been explained and demonstrated  [3,4]. Further, dynamic generation of webpages that include forms with captcha images can be achieved with various programming languages such as PHP, ASP, JSP, Perl, Python and Ruby [5].

What about identifying and appreciating the honest human being, who is interacting with your site; instead of targeting potential spambots all the time? Ben Hunt discusses a promising approach [6]. Invisibility is not only the strategy of spammers and spies, but can be derived by user-friendly technology, implemented as a backstage wizard that lets humans submit, sign in and hack as long as they employ finger work. Open creativity instead of captchability!

References and resources to explore
[1] www.captcha.net and www.google.com/recaptcha/captcha.
[2] TechnoFiles by David Pogue: Time to Kill Off Captchas. How the bot-proofing of the Internet in bringing humans down. Sci. Am. March 2012, 306 (3), page 23 [www.scientificamerican.com/article.cfm?id=time-to-kill-off-captchas].
[3] Simple JavaScript CAPTCHA Generator: typicalwhiner.com/190/simple-javascript-captcha-generator/.
[4] Implementation of Captcha in JavaScript: www.codeproject.com/Articles/42842/Implementation-of-Captcha-in-Javascript.
[5] Free CAPTCHA-Service: captchas.net.
[6] Ben Hunt:  CAPTCHA Alternative? Try this Invisible Human Check for Web Form Validation [www.webdesignfromscratch.com/javascript/human-form-validation-check-trick].