Escape from CAPTCHA
by
Matt May
Table of contents
Accessibility Problems with Visual Verification Systems
Escape from CAPTCHA
In the beginning...
Enter the bad guys
The showdown
What's a Turing test?
Who's trapping users?
The truth about cats and mice
Building a better mousetrap
Hierarchy of access
Privilege
Humanity
Identity
What is W3C doing about this?
Approach: logic
Approach: sound
Approach: credit-card validation
Approach: live operators
Approach: limited-use accounts
Approach: post-hoc checking
Approach: single sign-on
Approach: public-key infrastructure
Approach: biometrics
The wrap-up