Captcha is an automated security which is used to decide whether the web page is being used by the humans are the robots. It is a technology which present robots cannot pass through and is completely of puzzles, problems and pictures which humans can easily understand and pass through to it. The problems which are highly unsolvable to sort out are made easy for the highly successful for captcha which is designed to solve artificial intelligence problems Humans introduce a robotic test which present computers pass through and humans can easily have access through it. The problems which are highly unsolvable can be solved using captcha which have high success on artificial intelligence.
Captcha is used to decide whether you are human are not
Provides a puzzle which is difficult for computer and easy for humans
If the puzzle is solved you are considered as human, if not it is considered as robot
It is available in form of: –
Captcha which is in printed form is difficult to break
Lots of algorithms are present in market to generate this kind of captcha
This are very easy for humans to identify
There are two major types of text they are Baggle text, pessimal print
Baffle text uses pronounceable English characters which are not present in English dictionary
Pessimal text uses the degradation model simulating phusical defects caused by printing and scanning of printed text
Uses of transformations by adding lines, arcs, circles etc.
Uses of captcha
Free email services
Search engine bots
Prevention to worms and spams
Preventing dictionary attack etc.
Captcha should be automatically generated and graded
Test can be taken quickly and easily by human users
Test will accept virtually all humans users and reject software agents
Test will resist automatic attack for many years despite thee technology advances and prior knowledge of algorithms
Hopefuly, they will becoe more user-friendly to people with disabilities (visual, mental)
Captchas are mainly produced form AJAX and PHP technology
Various algorithms are present