Wednesday, February 22, 2012

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] and
[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 [].
[3] Simple JavaScript CAPTCHA Generator:
[4] Implementation of Captcha in JavaScript:
[5] Free CAPTCHA-Service:
[6] Ben Hunt:  CAPTCHA Alternative? Try this Invisible Human Check for Web Form Validation [].


  1. Computer Science
    Computer is an electronics device that can accept data and instructions as input, process the data to given instructions and shows results as output. Computer also has ability to store data and instructions. The physical and tangible parts of the computer are called “Hardware”. “Software’s” are intangible parts of the computer system.

  2. Computer Science
    I am very thankful your commenting and positng. It is related to computer.Computer is an electronics device that can accept data and instructions as input,process the data to given instructions and shows results as output.

  3. Computer Science
    I am very thankful your commenting and positng. It is related to computer.Computer is an electronics device that can accept data and instructions as input,process the data to given instructions and shows results as output.

  4. I would be flattened if all websites gave articles like that.

  5. Hi, I went through your this post and found

    really interesting. I landed this page through

    internet search and found
    this page very good.I am a web designer and

    works in a web design


    as a designer I liked the color of your blog



  6. wow thanks for providing so much informations about captcha......keep blogging

  7. its superb!
    the blog is very informative and useful.
    keep blogging.

    captcha solver

  8. wow!!!
    the great blog.the blog is very informative and very useful.
    thanks for sharing the info.
    keep blogging.

    Kill Captcha

  9. ya really useful this captcha Information to all easy to configure this captcha solutions mostly this information is authentic Article... This Captcha solution information way is Great... Thank you for your useful substance...

    Captcha Solving Services

  10. I happen to be commenting to let you know of the terrific encounter my cousin’s princess gained going through your blog. She learned a wide variety of pieces, including how it is like to have an incredible helping style to get other folks without hassle learn about a variety of complex subject areas. You truly did more than her expected results. Thanks for displaying the valuable, trusted, explanatory and even unique tips about your topic to her.
    How I can Create YouTube Channel?

  11. This comment has been removed by the author.

  12. Great post . It takes me almost half an hour to read the whole post. Definitely this one of the informative and useful post to me. Thanks for the share and plz visit my site Web Design Company Elesoftech is a leading offshare web development,mobile application, iphone application.

  13. Problem: HP Printer not connecting to my laptop.

    I had an issue while connecting my 2 year old HP printer to my brother's laptop that I had borrowed for starting my own business. I used a quick google search to fix the problem but that did not help me.

    I then decided to get professional help to solve my problem. After having received many quotations from various companies, i decided to go ahead with Online Tech Repair (

    Reasons I chose them over the others:
    1) They were extremely friendly and patient with me during my initial discussions and responded promptly to my request.
    2) Their prices were extremely reasonable.
    3) They were ready and willing to walk me through the entire process step by step and were on call with me till i got it fixed.

    How did they do it
    1) They first asked me to state my problem clearly and asked me a few questions. This was done to detect any physical connectivity issues with the printer.
    2) After having answered this, they confirmed that the printer and the laptop were functioning correctly.
    3) They then, asked me if they could access my laptop remotely to troubleshoot the problem and fix it. I agreed.
    4) One of the tech support executives accessed my laptop and started troubleshooting.
    5) I sat back and watched as the tech support executive was navigating my laptop to spot the issue. The issue was fixed.
    6) I was told that it was due to an older version of the driver that had been installed.

    My Experience
    I loved the entire friendly conversation that took place with them. They understood my needs clearly and acted upon the solution immediately. Being a technical noob, i sometimes find it difficult to communicate with tech support teams. It was a very different experience with the guys at Online Tech Repairs. You can check out their website or call them on 1-914-613-3786.
    Would definitely recommend this service to anyone who needs help fixing their computers.
    Thanks a ton guys. Great Job....!!