Patent ID: 7353994
Filing Date: 2008-04-08
Classification: G06K,G07D,G07F,G08B

Abstract:
1. A method of operating a security system, said method comprising: making a plurality of tags, each of which includes a plurality of particles randomly distributed in a light-transmitting matrix; attaching the tags to objects to be authenticated; providing a reader which includes means for causing light of one or more wavelengths to impinge on a tag and means for detecting, recording and interpreting the light reflected and/or refracted and/or diffracted by the particles in the matrix so as to produce images of the particles; presenting said tags to said reader; encrypting and storing information concerning the images of at least some of the particles of a particular tag on at least one of the particular tag and the object to which the particular tag is attached; recalling and decrypting the encrypted image information; and comparing the recalled and decrypted image information with the image information obtained by the reader when authentication is required.