Two Security Problems of Efficient Remote Mutual Authentication and Key Agreement

In the ubiquitous environments, smart cards as an ubiquitous computing device provide several services to pervasive computing and ubiquitous services. In 2006, Shieh-Wang pointed out the weakness of Juang's remote mutual authentication scheme using smart card and further proposed a novel remote user authentication scheme using smart card. The current paper, however, demonstrates that Shieh-Wang's scheme does not provide perfect forward secrecy and is vulnerable to a privileged insider's attack.