Accessibility of CAPTCHA methods
Proceedings of the 4th ACM workshop on Security and artificial intelligence
Text-based CAPTCHA strengths and weaknesses
Proceedings of the 18th ACM conference on Computer and communications security
SEMAGE: a new image-based two-factor CAPTCHA
Proceedings of the 27th Annual Computer Security Applications Conference
Security and usability challenges of moving-object CAPTCHAs: decoding codewords in motion
Security'12 Proceedings of the 21st USENIX conference on Security symposium
PUBCRAWL: protecting users and businesses from CRAWLers
Security'12 Proceedings of the 21st USENIX conference on Security symposium
SeeSay and HearSay CAPTCHA for mobile interaction
Proceedings of the SIGCHI Conference on Human Factors in Computing Systems
A survey and analysis of current CAPTCHA approaches
Journal of Web Engineering
| Hi-index | 0.00 |
CAPTCHAs, which are automated tests intended to distinguish humans from programs, are used on many web sites to prevent bot-based account creation and spam. To avoid imposing undue user friction, CAPTCHAs must be easy for humans and difficult for machines. However, the scientific basis for successful CAPTCHA design is still emerging. This paper examines the widely used class of audio CAPTCHAs based on distorting non-continuous speech with certain classes of noise and demonstrates that virtually all current schemes, including ones from Microsoft, Yahoo, and eBay, are easily broken. More generally, we describe a set of fundamental techniques, packaged together in our Decaptcha system, that effectively defeat a wide class of audio CAPTCHAs based on non-continuous speech. Decaptcha's performance on actual observed and synthetic CAPTCHAs indicates that such speech CAPTCHAs are inherently weak and, because of the importance of audio for various classes of users, alternative audio CAPTCHAs must be developed.