Attacking image recognition CAPTCHAS: a naive but effective approach
TrustBus'10 Proceedings of the 7th international conference on Trust, privacy and security in digital business
Distinguishing distributions using Chernoff information
ProvSec'10 Proceedings of the 4th international conference on Provable security
AniCAP: an animated 3d CAPTCHA scheme based on motion parallax
CANS'11 Proceedings of the 10th international conference on Cryptology and Network Security
Enhanced STE3D-CAP: a novel 3d CAPTCHA family
ISPEC'12 Proceedings of the 8th international conference on Information Security Practice and Experience
A survey and analysis of current CAPTCHA approaches
Journal of Web Engineering
| Hi-index | 0.00 |
CAPTCHAs have been widely used across the Internet to defend against undesirable or malicious bot programs. In this article, the authors describe the security of a CAPTCHA reported in a recent peer-reviewed paper and deployed on the Internet. They show that although this scheme was effectively resistant to one of the best optical character recognition programs on the market, they could break it with a success rate of higher than 90 percent by using a simple but novel attack. In contrast to early work that relied on sophisticated computer vision or machine learning algorithms, they used simple pattern recognition algorithms that exploited fatal design errors. The main contribution of their work is that simply counting the pixels in a CAPTCHA's characters can be a very powerful attack.