We introduce captcha, an automated test that humans can pass, but current computer programs can’t pass: any program that has high success over a captcha can be used to solve an u...
Luis von Ahn, Manuel Blum, Nicholas J. Hopper, Joh...
—Captchas are designed to be easy for humans but hard for machines. However, most recent research has focused only on making them hard for machines. In this paper, we present wha...
Elie Bursztein, Steven Bethard, Celine Fabry, John...
- Vulnerabilities related to weak passwords are a pressing global economic and security issue. We report a novel, simple, and effective approach to address the weak password probl...
— Today sending spams has turned to be a major problem in the Internet. It is so serious that more than 80% of the transferred emails are spams. As a result, various methods have...
The ASIRRA CAPTCHA [6], recently proposed at ACM CCS 2007, relies on the problem of distinguishing images of cats and dogs (a task that humans are very good at). The security of AS...