Patent ID: 7475812

Claim:
A security system for access control using smart card badges each having a unique Smart Card Serial Number onto which is stored a unique Credential Identifier, in which said security system has a Site Secret Key, said system comprising: at least one access controller having a database storing for each one of a plurality of smart card badges at least a Credential Identifier and an encrypted Authorization Code as a badge number and an issue code, respectively, for the smart card badge, and access privilege data; one or more readers in which each of said readers when presented with one smart card badge of said plurality of smart card badges reads the Credential Identifier and Smart Card Serial Number from said one smart card badge, generates an encrypted Authorization Code based on the read Credential Identifier and Smart Card Serial Number, and a Site Secret Key stored in the reader, and sends a request to the access controller with at least the read Credential Identifier and generated Authorization Code; and said access controller receives the Credential Identifier and the Authorization Code of the request as the badge number and the issue code for said one smart card badge, respectively, and makes access decision as to whether the badge number and the issue code for said one smart card badge matches one of the badge number and issue code for one of the plurality of smart card badges stored in the database of the access controller, and whether said one smart card badge has access privileges at the reader which sent said request in accordance with said access privileges data for said one smart card badge in said database of the access controller.