Improvements of Juang et al.'s password-authenticated key agreement scheme using smart cards

In the IEEE Transactions on Industrial Electronics, vol. 55, no. 6, Juang et al proposed a password-authenticated key agreement scheme using smart cards. Although the scheme of Juang et al has many benefits, we find that it suffers from three weaknesses: 1) inability of the password-changing operation; 2) the session-key problem; and 3) inefficiency of the double secret keys. Therefore, we propose an improved scheme to overcome the weaknesses and maintain the benefits of the original scheme. In addition, our improved scheme reduces the storage and computation costs on the smart card compared with the scheme of Juang et al We believe that our improved scheme is more suitable for real-life applications than that of Juang et al.