Patent ID: 7237115
Filing Date: 2007-06-26
Classification: H04L

Abstract:
1. A method of authenticating an item, the method comprising: a) acquiring an unencrypted reference signal, Y b) applying a transformation to the unencrypted reference signal, Y c) acquiring an unencrypted new signal, Y d) applying the transformation to the unencrypted new signal, Y e) calculating an unencrypted Euclidean distance metric, E, between the unencrypted new and reference signals, Y f) calculating an encrypted Euclidean distance metric, D, between the encrypted new and reference measurements, U g) comparing the encrypted Euclidean distance metric, D, to a critical value, D h) if D<D i) providing the result of the decision made in step h) to an authenticator or inspector, thereby allowing the authenticator or inspector to decide if the item is authentic; wherein the transformation has the property that the unencrypted Euclidean distance metric, E, is equal to the encrypted Euclidean distance metric, D.