Authentication server for use in electronic transaction field, has synchronization unit that is controlled based on reception of password and verification of compliance of predefined criterion related to received password

摘要

The server (14) has a generating unit (24) for generating a version of a dynamic password based on a value of a counter (22) for verifying the correspondence between the version and a password generated based on a value of another counter external to the server. A synchronization unit synchronizes the counters. The synchronization unit is controlled based on the reception of a password with synchronization length greater than a predefined length and based on the verification of compliance of a predefined criterion related to the received password. Independent claims are also included for the following: (1) a system for authentication from dynamic passwords, comprising an authentication server (2) a method for authentication from dynamic passwords of predefined lengths.