PHAN, R.C.-W. and GOI, B.-M., 2004. Further attacks and comments on 'security of two remote user authentication schemes using smart cards'. IEEE Transactions on Consumer Electronics, 50(2), pp. 609 - 611
We point out that Hsu's recent cryptanalysis of Sun's remote user authentication scheme is flawed. We also comment on Chien et. al's scheme and give more practical attacks than those presented by Hsu in the same paper.