SP
2010
IEEE
14 years 3 months ago
2010
IEEE
—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...
CHI
2009
ACM
15 years 3 days ago
2009
ACM
Audio CAPTCHAs were introduced as an accessible alternative for those unable to use the more common visual CAPTCHAs, but anecdotal accounts have suggested that they may be more di...