A
Ahmad Salah El Ahmad
Researcher at Newcastle University
Publications - 6
Citations - 838
Ahmad Salah El Ahmad is an academic researcher from Newcastle University. The author has contributed to research in topics: CAPTCHA & Security engineering. The author has an hindex of 5, co-authored 6 publications receiving 801 citations.
Papers
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Proceedings ArticleDOI
A low-cost attack on a Microsoft captcha
Jeff Yan,Ahmad Salah El Ahmad +1 more
TL;DR: It is shown that CAPTCHAs that are carefully designed to be segmentation-resistant are vulnerable to novel but simple attacks, including the schemes designed and deployed by Microsoft, Yahoo and Google.
Proceedings ArticleDOI
Usability of CAPTCHAs or usability issues in CAPTCHA design
Jeff Yan,Ahmad Salah El Ahmad +1 more
TL;DR: Usability issues that should be considered and addressed in the design of CAPTCHAs are discussed, and a simple but novel framework for examining CAPTCHA usability is proposed.
Proceedings ArticleDOI
The robustness of a new CAPTCHA
TL;DR: This paper shows that this new CAPTCHA scheme deployed until very recently by Megaupload can be segmented using a simple but new automated attack with a success rate of 78%.
Journal ArticleDOI
Captcha Robustness: A Security Engineering Perspective
Jeff Yan,Ahmad Salah El Ahmad +1 more
TL;DR: Captchas are a standard defense on commercial websites against undesirable or malicious Internet bot programs, but widely deployed schemes can be broken with simple but novel attacks.
Colour, usability and security: a case study
Ahmad Salah El Ahmad,Jeff Yan +1 more
TL;DR: It is shown that the use of colours in the design of CAPTCHA, a standard security technology that has found widespread applications in commercial websites, can have critical implications on both security and usability.