Cryptanalysis of Improved Password Authentication Scheme with Smart Cards

스마트 카드에서 향상된 비밀번호 인증 암호해독기법

The intent of this paper is to present the flaws and weaknesses of Kim et al.'s timestamp-based password authentication scheme using smart cards. We prove that, in spite of the improvement of Yang-Wang-Chang's scheme, Kim et al.'s solution is still vulnerable to a type of forgery attack. We also note down how the flaw could be overcome to ensure better level of security in remote client-server communication procedure.