%0 Journal Article %T Improved G-3PAKE Protocol with Formal Verification %A Manju Sanghi %J International Journal of Information and Network Security (IJINS) %D 2012 %I Institute of Advanced Engineering and Science (IAES) %R 10.11591/ijins.v1i1.249 %X In 2007, Lu and Cao proposed a simple three party password authenticated key exchange (S-3PAKE) protocol. In 2008, Guo et al. have shown that S-3PAKE protocol is completely insecure against man-in-the-middle attack and undetectable on-line password guessing attack. They also provided an improved protocol (G-3PAKE) that addresses the identified security problems. Recently, Choi and Yoon have demonstrated that G-3PAKE protocol still falls prey to undetectable on-line password guessing attack by any other client. In the present paper we propose an improved G-3PAKE protocol which can resist all the known attacks along with its formal proof. %U http://www.iaesjournal.com/online/index.php/IJINS/article/view/249