Science & Engineering Research Support soCiety (SERSC)
In wireless environments, the issue of mutual authentication and key agreement with user anonymity is challenging. Recently, a researcher proposed an efficient anonymous authentication scheme for roaming services in wireless environments. Unfortunately, other researcher pointed out that anonymous authentication scheme suffers from replay attacks and man-in-the-middle attacks. They propose an improved secure anonymous authentication scheme for roaming services. Researcher claimed that their protocol removed the weaknesses of the previous scheme. However, the authors show that second researcher scheme fails to achieve anonymity.