Time-accounting system and method comprising means for the generation of codes at instants computed by a secret algorithm

Abstract From the Canadian patent

A device that can be used to check the authenticity of time-accounting systems and devices, and notably of time-accounting devices for reckoning periods of parking regulated by rules. The system is constituted by a plurality of boxes each, held by a distinct user, each box comprising computation means that determine atleast two secret codes the changing from one secret code to another being done substantially at one and the same instant for all of boxes and secret codes being identical for all of boxes substantially at the same instant to enable a checker to ascertain the authenticity of boxes, code-changing instant resulting from a secret computation.