Abstract: In Public Wireless LANs(PWLANs), user anonymity
is an essential issue. Recently, Juang et al. proposed an anonymous
authentication and key exchange protocol using smart cards in
PWLANs. They claimed that their proposed scheme provided identity
privacy, mutual authentication, and half-forward secrecy. In this paper,
we point out that Juang et al.'s protocol is vulnerable to the
stolen-verifier attack and does not satisfy user anonymity.