Mobile one-time passwords: two-factor authentication using mobile phones

Static password authentication has security drawbacks. In two-factor authentication (2FA,) each user carries a device, called token, to generate passwords that are valid only one time. 2FA based on one-time passwords (OTPs) provides improved protection because users are prompted to provide something they know (i.e., PIN) and something they have (i.e., token). Many systems have satisfied the 2FA requirements by sending an OTP through an SMS to the user's phone device. Unfortunately, international roaming, and SMS costs, delays, and security put restrictions on this system reliability. Also, time synchronous-based solutions are not applicable for mobile phones. In this paper, we present a novel 2FA scheme whereby multiple OTPs are being produced by utilizing an initial seed and two different nested hash chains: one dedicated to seed updating and the other used for OTP production. We overcome all the restrictions that come from other techniques. We analyze our proposal from the viewpoint of security and performance compared with the other algorithms. Copyright (c) 2011 John Wiley & Sons, Ltd.