Acronym: CAPTCHA=Completely Automated Public Turing test to tell Computers and Humans Apart
He is the most easy way to make difference between Human and Bot. Sometimes he bother us, but he make his job.
A CAPTCHA system is a means of automatically generating new challenges which:
Current software is unable to solve accurately.
Most humans can solve.
Does not rely on the type of CAPTCHA being new to the attacker.
Most requently, a CAPTCHA features an image file of slightly distorted alphanumeric characters.
A human can usually read the characters in the image without too much difficulty. A bot program is able to recognize that the content contains an image , but it has no idea what the image is.
To accomodate the visually-impaired, some CAPTCHAs use audio files. In such a system, the human listens to a series of letters or short words and types what he hears to prove he is not a bot.
No comments:
Post a Comment