Importance

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Abstract

This invention describes a system for access control, wherein a control card is presented to a control means. If the control card is authenticated, then access is gained. If it is not authenticated, access is not gained, the control card is retained, and an alarm may be sounded. The control card contains at least two means; (1) machine readable indicia identifying the card, and (2) a random pattern of micro spots, which pattern is derived (by direct copying--such as by focussed laser beam) from one of a plurality of different patterns, retained in a bank of such micro patterns, each such micro pattern identified by, and selectable in accordance with, different unique indicia, identical with the machine readable indicia on said cards. In use the control card is introduced into the control means and the indicia are read. Master micro pattern corresponding to the indicia is selected from the bank. The card micro pattern and master micro pattern are compared. If the comparison okay, the card is authenticated.

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First Claim