| The memorability and security of passwords–some empirical results J Yan, A Blackwell, R Anderson, A Grant University of Cambridge, Computer Laboratory, 2000 | 1069* | 2000 |
| Security and usability: designing secure systems that people can use LF Cranor, S Garfinkel " O'Reilly Media, Inc.", 2005 | 679 | 2005 |
| A Low-cost Attack on a Microsoft CAPTCHA J Yan, AS El Ahmad Proceedings of the 15th ACM conference on Computer and communications …, 2008 | 585 | 2008 |
| Usability of CAPTCHAs or usability issues in CAPTCHA design J Yan, AS El Ahmad Proceedings of the 4th symposium on Usable privacy and security, 44-52, 2008 | 420 | 2008 |
| Targeted Online Password Guessing: An Underestimated Threat D Wang, Z Zhang, P Wang, J Yan, X Huang ACM Conference on Computer and Communications Security (CCS), 2016 | 412 | 2016 |
| Breaking visual captchas with naive pattern recognition algorithms J Yan, AS El Ahmad ACSAC'07, Twenty-Third Annual Computer Security Applications Conference …, 2007 | 371 | 2007 |
| Do background images improve draw a secret graphical passwords? P Dunphy, J Yan Proceedings of the 14th ACM conference on Computer and communications …, 2007 | 334 | 2007 |
| A systematic classification of cheating in online games J Yan, B Randell Proceedings of 4th ACM SIGCOMM workshop on Network and system support for …, 2005 | 293 | 2005 |
| Attacks and design of image recognition CAPTCHAs BB Zhu, J Yan, Q Li, C Yang, J Liu, N Xu, M Yi, K Cai Proceedings of the 17th ACM conference on Computer and communications …, 2010 | 202 | 2010 |
| Captcha as Graphical Passwords–A New Security Primitive Based on Hard AI Problems BB Zhu, J Yan, G Bao, M Yang, N Xu IEEE transactions on information forensics and security 9 (6), 891-904, 2014 | 201 | 2014 |
| Shoulder surfing defence for recall-based graphical passwords NH Zakaria, D Griffiths, S Brostoff, J Yan Proceedings of the seventh symposium on usable privacy and security, 1-12, 2011 | 185 | 2011 |
| Security issues in online games J Yan, HJ Choi The Electronic Library 20 (2), 125-133, 2002 | 175 | 2002 |
| The memorability and security of passwords–some empirical results J Yan, A Blackwell, R Anderson, A Grant University of Cambridge, Computer Laboratory, 2000 | 168 | 2000 |
| The memorability and security of passwords–some empirical results J Yan, A Blackwell, R Anderson, A Grant University of Cambridge, Computer Laboratory, 2000 | 168 | 2000 |
| A note on proactive password checking J Yan Proceedings of the 2001 workshop on New security paradigms, 127-135, 2001 | 146 | 2001 |
| The robustness of Google CAPTCHAs AS El Ahmad, J Yan, M Tayara Newcastle University, School of Computing Science Technical Report Series, 2011 | 129* | 2011 |
| A Simple Generic Attack on Text Captchas. H Gao, J Yan, F Cao, Z Zhang, L Lei, M Tang, P Zhang, X Zhou, X Wang, ... NDSS, 2016 | 118 | 2016 |
| The robustness of hollow captchas H Gao, W Wang, J Qi, X Wang, X Liu, J Yan Proceedings of the 2013 ACM SIGSAC conference on Computer & communications …, 2013 | 103 | 2013 |
| The robustness of a new CAPTCHA AS El Ahmad, J Yan, L Marshall Proceedings of the Third European Workshop on System Security, 36-41, 2010 | 103 | 2010 |
| CAPTCHA design: Color, usability, and security AS El Ahmad, J Yan, WY Ng IEEE Internet Computing 16 (2), 44-51, 2012 | 95 | 2012 |
Ahmad S. El AhmadPhD Computer Science, Newcastle UniversityVerified email at ncl.ac.uk
