关键词: 一次性口令, 身份认证, S/KEY认证

Abstract: The author analyzed some defects of the traditional S/KEY One-Time Password (OTP) authorization scheme and recent improvements, and proposed a new S/KEY improvement scheme. The new scheme provided mutual authorization with Hash values of user password as an authentication factor. It can effectively prevent key message from being forged by adding message integrity protection. The new scheme is as simple and easy to be implemented as traditional S/KEY scheme. Additionally, it can effectively avoid replay attack, small integer attack and impersonating attack.

Key words: One-Time Password (OTP), identity authorization, S/KEY authorization