Controlling access to an area

Abstract From the Canadian patent

Controlling access includes providing a barrier to access that includes a controller that selectively allows access at least one administration entity , generating credentials/proofs wherein no valid proofs are determinable given only the credentials and values for expired proofs the controller receiving , the credentials/proofs (152 154), the controller determining if access is presently authorized, and, if access is presently authorized the controller , allowing access (168). The credentials/proofs may be in one part or may be in separate parts (152, 154). There may be a first administration entity that generates the credentials (154) and other administration entities that generate …