US 6,888,442 B1 · Substrate/document authentication using randomly dispersed dielectric components

Abstract

A document verification scheme embeds in or deposits on a substrate/document a random distribution of dielectric particles that effectively create a unique electronically detectable signature. The dielectric constant of the particles is sufficiently larger than that of the substrate/document, so as to exhibit molecular level electric dipole moments, which cause a detectable modification of an external electric field passing through the substrate. Electronic signature verification is effected by comparing the digitized output of an electric field modification sensor with a digital code that has been stored previously in the data base. As long as the substrate containing the dielectric particle signature has not been altered, its randomly distributed capacitance characteristic will remain unchanged, and the two digital signatures seen by the comparator will effectively match one another, verifying authentication of the substrate. However, alteration of the substrate and thereby the particle distribution will modify the capacitance characteristic associated with the randomly distributed particles and cause the comparator to be presented with two diverse digital signatures—indicating tampering.

Claims15

Dependent claims

A method of processing a substrate to impart a security identification thereto comprising the steps of:

(a) affixing a random distribution of dielectric components with said substrate, said dielectric components having a dielectric constant sufficiently larger than that of said substrate as to exhibit molecular level electric dipole moments that cause a detectable modification of an external electric field passing through said substrate in accordance with said random distribution;
(b) coupling said substrate, to which said random distribution of dielectric components has been affixed in step (a), with an electric field;
(c) measuring a modification of said electric field with which said substrate is coupled in step (b), and generating an output signal representative of said modification;
(d) storing information representative of said output signal in a storage medium separate from said substrate;
(e) coupling said substrate, to which said random distribution of dielectric components has been affixed in step (a), with an electric field;
(f) measuring a modification of said electric field with which said substrate is coupled in step (e), and generating an information signal representative of the measured modification;
and
(g) comparing contents of said information signal generated in step (f) with said information stored in said storage medium in step (d), to verify the validity of said substrate.

5 more elements

Dependencies are inferred from the claim text.

Substrate/document authentication using randomly dispersed dielectric components

Life of this patent

Substrate/document authentication using randomly dispersed dielectric components

Life of this patent

Abstract

Claims15