Cryptanalysis of a Recent Two Factor Authentication Scheme

Two factor authentication schemes which support a range of desirable attributes, have proven difficult to develop. In two existing schemes are successfully cryptanalysis, and a new scheme is proposed. Here the authors analyze this new scheme and point out some problems with it. In one sense it is not hard to develop a two factor authentication scheme based on a password and on possession of a token. Very recently a scheme has been proposed by Wang and Ma for a robust smart-card based password authentication scheme, which claims to be secure against a Smart Card security breach. In this short note they attempt an initial cryptanalysis of this scheme.