  Since 1981, when Lamport introduced the remote user authentication scheme
using table, a plenty of schemes had been proposed with tables or without table
using. Recently Das et al. proposed a dynamic id-based remote user
authentication scheme. They claimed that their scheme is secure against
ID-theft, and can resist the reply attacks, forgery attacks, insider attacks an
so on. In this paper we show that Das et al's scheme is completly insecure and
using of this scheme is like an open server access without password.
