关键词: 密码验证, 猜测攻击, Smart Card

Abstract: Authentication is an issue of importance in computer communications, and password authentication protocols have been widely utilized due to their great convenience. Recently, Lee et al. proposed a nonce-based remote user authentication scheme using smart cards. In this paper, however, it is found that their scheme is not secure as claimed, and two attacks can be launched to break the scheme.

Key words: password authentication, guessing attack, Smart Card