Analysis of untraceable dynamic identity based remote user authentication scheme

In this world of e-technology, two users/systems requires to authenticate each other before exchanging the information. For this, there are numerous schemes proposed and analyzed for authentication. Indeed, in 2013, Chang et al.´s proposed an efficient untraceable dynamic identity system based on remote user authentication and claimed that the scheme is secure against various attack. In opposition, in this paper we have identified that Chang et al.´s scheme is vulnerably susceptible to the attacks like Plain Text, Smart Card Lost, Denial of Service and Parallel Session.