method for performing manual clock synchronization on devices running applications with safety requirements

摘要

method for manually synchronizing clocks on devices running applications with safety requirements. The method in question allows clocks (13, 23) used by applications on different devices, such as a cell phone (10) and an authentication server (20) of an institution (2) to be synchronized with each other. The method is particularly suited for security applications such as time tokens (13), mobile device (dm), pending synchronization with authentication server (20) or other time source running on mobile devices (dm) , such as mobile phones (10), PDAs and notebooks. a token clock (14) is provided, which is based on a server clock (23) and a device clock (12). when an authentication application (22) detects that token clock (14) is offset from server clock (23) 1 a resynchronization operation is initiated, generating a synchronization data to be entered by the user in the temporal token application (13) and which is calculated from a reduced representation of the server clock value (23) through a reduced and encrypted function using a small block size algorithm. This value is entered by the user and the inverse calculation is performed by the temporal token application (12) and the result is used to calculate the value of the token clock (14). an otp is immediately generated by the temporal token application (13) and used to authenticate the user at this time of synchronization.