About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
ASIACCS 2011
Conference paper
Attack on the GridCode one-time password
Abstract
SyferLock presents a one-time password system, GridCode, that allows an unaided human to authenticate, reducing the cost of deployment. The one-time password system is a human computable challenge-response protocol which they claim defends against key-logging, replay, and brute force attacks, among others. We evaluate the security of the GridCode one-time password system and challenge these claims. We identify weak preimage resistance and character independence as key weaknesses of the GridCode system, leading to a variety of attacks. Our analysis indicates their scheme is akin to providing an adversary the ability to perform a brute force attack on a user's password in parallel without significant effort, lowering the effort required to recover a strong user password. Given a small number of challengeresponse pairs, an adversary can recover a user's password (e.g., 2-4 pairs), and additional secret (e.g., 1 pair). Copyright 2011 ACM.