Sciweavers

USS
2010
13 years 9 months ago
Re: CAPTCHAs-Understanding CAPTCHA-Solving Services in an Economic Context
Reverse Turing tests, or CAPTCHAs, have become an ubiquitous defense used to protect open Web resources from being exploited at scale. An effective CAPTCHA resists existing mechan...
Marti Motoyama, Kirill Levchenko, Chris Kanich, Da...