A Security and Efficiency Authentication Scheme Based on Human-memorable Password

From the view point of users, security and efficiency are two main factors for any authentication scheme. It's particularly important in multi-server architecture authentication protocol, because users can login many servers with only one password and one identity. In practical cases, users usually choose the password that can be remembered easily (human-memorable), which has low entropy and can be guessed out in short time. In 2010, Shao-Chin proposed a multi-server authentication protocol which was based on dynamic identity. We find that their scheme could not resist password guessing attack, user impersonation attack and do not have anonymity. For these concerns, we propose a multi-server authentication scheme based on two-factor, which can raise efficiency of communication and calculation by reducing unnecessary steps of keys exchange. In addition, the scheme has higher security which makes up for above-mentioned security flaws.