User authentication with the help of simple memory devices

We propose a slmple and secure user authentication method with the help of slmple memory devices such as magnetic cards. In this method, user's password is divided into two pieces; one is kept in the user's mind and the other is stored in the memory device. The original password is recoistructed if and only if both of them are presented. The contents of the memory device are encrypted so that the robbery of the card does not effect to the security of the method. Furthermore, the contents of the device are changed in every session, which makes the method robust against replay attacks and minimizes the damage of the user in case of an emergency. Using this method, we can easily overcome the problem of impersonation of an intruder caused by network attacks, a fault of users, illegal copy of the card and so on. We give the definition of the method and discuss its security.http://library.naist.jp/mylimedio/dllimedio/show.cgi?bookid=100009594&oldid=1690