Techniques for providing authentication functionality in a gaming system are disclosed. In one aspect, a gaming system is configured such that, at a given point during a current session of a game in progress that involves at least one user previously granted access by the system to participate in the current session, information available from an authentication token associated with the user is obtained prior to allowing the user to take a particular action in the game. A determination is made as to whether or not the user will be allowed to take the particular action in the game, based on the obtained information. The obtained information may comprise, for example, at least a portion of a one-time password generated by a hardware or software authentication token.