Patent ID: 9654467
Date: 2017-05-16
CPC Classifications: H04L

Claim:
1. A token-side method for generating a passcode from a user authentication token for presentation to an authentication server, comprising: receiving a request to generate said passcode at a current device time of said user authentication token; detecting, by at least one processing device of said user authentication token that generates said passcode, a previous forward clock attack during said generation of said passcode, wherein a third party actor implemented said forward clock attack by altering a device time of said user authentication token to a time that is later than said current device time of said user authentication token, accessing at least one passcode that is valid at said time that is later than said current device time and restoring said device time to a substantially current time of said forward clock attack, wherein said forward clock attack is detected by determining whether said current device time of said user authentication token is less than a last used device time indicating a last time that said user authentication token was used to produce a last passcode, wherein said last used device time is stored as part of a state of said user authentication token, wherein said last used device time is updated to said current device time during said generation of said user authentication passcode; and communicating, by said user authentication token, an indication of said forward clock attack to said authentication server, wherein said authentication server re-synchronizes with said user authentication token in response to said indication from said user authentication token of said forward clock attack.