25-08-2017, 09:32 PM
IMPROVING STRENGTH OF CAPTCHA
54426038-captcha arpi.ppt (Size: 780 KB / Downloads: 54)
What is CAPTCHA
Completely Automated Public Turing Test To Tell Computer And Human Apart.
Used to protect resources like emails from “bot’s” attacks
.should be automated, usable and secure
e.g..:
NEED OF BREAKING CAPTCHA
We want to improve the current strength of network and for that we have to break the existing CAPTCHAS.
Once broken it would also help the genuine downloader who waste hundreds of hours in entering the CAPTCHA values yearly.
Breaking a Visual CAPTCHA
The most widely used CAPTCHA is the visual CAPTCHA.
Breaking it involves mainly 2 steps
Segmentation
Identification
Before segmentation we also perform some preprocessing on the image to remove the background and some noise.