INFORMATICA Informatica 1822-8844 0868-4952 0868-4952 Vilnius University Institute of Mathematics and Informatics Akademijos 4, LT-08663 Vilnius, Lithuania INFO575 10.15388/Informatica.2005.082 Research Article Cryptanalysis of the Modified Remote Login Authentication Scheme Based on a Geometric Approach Chang Chin-Chen ccc@cs.ccu.edu.tw a Lin Iuon-Chang iclin@cs.kuas.edu.tw b Department of Computer Science and Information Engineering, National Chung Cheng University, 60, San-Hsing, Min-Hsiung, Chiayi 621, Taiwan Department of Management Information System, National Chung Hsing University, 250 Kuo Kuang Road, 402 Taichung, Taiwan 2005 16 1 37 44 1 11 2001 © 2005 Institute of Mathematics and Informatics, Vilnius 2005 Open access article under the CC BY license.

In 1995, Wu proposed a remote login authentication scheme based on geometric approach. However, Chien, Jan and Tseng presented a cryptanalysis of Wu’s scheme to show that it is not secure. Moreover, they proposed a modified version of Wu’s scheme. This paper presents there is a serious weakness in this modified remote login authentication scheme. We show that an illegal user can easily forge a valid login request in the modified version proposed previously.

 cryptography remote login