1. A method for controlling access by a requesting entity to an asset, comprising: defining an approved state of the requesting entity; obtaining from an event validation system a validation of a representation of the approved state of in a non-repudiatable form; triggering the requesting entity to determine a current state of said requesting entity; comparing the current state with the approved state; and allowing access by the requesting entity to the asset only if the current state is the same as the approved state.