Home | Blog | Software | Reviews and Features | Forum | Help | Donate | About us

avatar image

Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
  • October 26, 2016, 01:01:26 AM
  • Proudly celebrating 10 years online.
  • Donate now to become a lifetime supporting member of the site and get a non-expiring license key for all of our programs.
  • donate

Author Topic: Interesting Article on CAPTCHA and OCR  (Read 3600 times)


  • Supporting Member
  • Joined in 2007
  • **
  • Posts: 1,237
    • View Profile
    • Donate to Member
Interesting Article on CAPTCHA and OCR
« on: August 26, 2008, 08:40:22 PM »
An interesting essay from those that broke the Yahoo CAPTCHA.
CAPTCHA - «Completely Automated Public Turing test to tell Computers and Humans Apart» [1]. Any problem that can be easily solved by a human, but cannot be solved by a computer (or which requires excessive computation), can be used as a Turing test. To protect against auto registration, mass mailing in forums and guestbooks, a text-based CAPTCHA was chosen (we will reference it as text-CAPTCHA below). Initially text-CAPTCHA was used in 1997 by AltaVista search system to protect against automated URLs (Uniformed Resource Locator) submitting. An example of a such CAPTCHA is shown on Figure 1. Since then, this type of protection was adopted by other resources: free mail services, blogs, social networks, etc.

Full Story


Fred Nerd

  • Supporting Member
  • Joined in 2006
  • **
  • Posts: 278
    • View Profile
    • Donate to Member
Re: Interesting Article on CAPTCHA and OCR
« Reply #1 on: August 30, 2008, 04:05:45 AM »
Good find, interesting
 :Thmbsup: :Thmbsup: :Thmbsup:


  • Charter Member
  • Joined in 2006
  • ***
  • Points: 1
  • Posts: 7,682
    • View Profile
    • The Blog of Deozaan
    • Read more about this member.
    • Donate to Member
Re: Interesting Article on CAPTCHA and OCR
« Reply #2 on: August 31, 2008, 04:37:49 PM »
A bit beyond my level of understanding, but at least the pictures were pretty.  ;)