Magnetic helical physical unclonable function measured above flight

Patent metadata

Field	Value
Publication number	US-9542576-B1
Application number	US-201615227633-A
Country	US
Kind code	B1
Filing date	Aug 3, 2016
Priority date	Aug 3, 2016
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

A helical physical unclonable function is disclosed. The helical physical unclonable function may be used to authenticate a supply item for an imaging device. Measurements of the magnetic field above a helical flight are stored in a non-volatile memory to be used by an imaging device to authenticate the supply item. Other systems and methods are disclosed.

First claim

What is claimed is:

1. A supply item for an image forming device comprising:
a body;
a physical unclonable function located on the body configured to rotate about an axis of rotation having a shaft centered on the axis of rotation and a helical flight having a length wrapped around the shaft, the helical flight has a top surface furthest away from the axis of rotation, the helical flight contains magnetized particles that generate a magnetic field above the top surface having a varying intensity along the length of the helical flight, the helical flight has a side surface between the shaft and the top surface; and
a non-volatile memory located on the body containing a first array of numbers corresponding to the intensity of the magnetic field radial to the axis of rotation above the top surface along a section of the length of the helical flight at a first plurality of locations each at a first fixed distance from the side surface and also containing a digital signature generated from the first array of numbers.

2. The supply item of claim 1 , wherein the physical unclonable function is configured to slide laterally along a drive shaft located on the axis of rotation.

3. The supply item of claim 1 , wherein the non-volatile memory contains a second array of numbers corresponding to the intensity of the magnetic field radial to the axis of rotation above the top surface at a second plurality of locations each located a second fixed distance from the side surface.

4. The supply item of claim 1 , wherein the non-volatile memory contains a third array of numbers corresponding to the intensity of the magnetic field parallel to the axis of rotation above the top surface along the section of the length of the helical flight at the first plurality of locations.

5. The supply item of claim 1 , wherein the helical flight has a rectangular cross section.

6. The supply item of claim 1 , wherein the helical flight has a semi-circular cross section.

7. The supply item of claim 1 , wherein the section of the length of the helical flight has a helix angle between thirty degrees and sixty degrees inclusive.

8. The supply item of claim 1 , wherein the digital signature is generated using asymmetric cryptography.

9. A supply item for an image forming device comprising:
a body;
a physical unclonable function located on the body configured to rotate about an axis of rotation having a shaft centered on the axis of rotation, the shaft has a helical channel having a length wrapped around the shaft, the shaft contains magnetized particles that generate a magnetic field above the shaft having a varying intensity, the helical channel has a side surface; and
a non-volatile memory located on the body containing a first array of numbers corresponding to the intensity of the magnetic field radial to the axis of rotation above the shaft along a section of the length of the helical channel at a first plurality of locations each at a first fixed distance from the side surface and also containing a digital signature generated from the first array of numbers.

10. The supply item of claim 9 , wherein the physical unclonable function is configured to slide laterally along a drive shaft located at the axis of rotation.

11. The supply item of claim 9 , wherein the side surface is planar.

12. The supply item of claim 9 , wherein the side surface is curved.

13. The supply item of claim 9 , wherein the section of the length of the helical channel has a helix angle between thirty degrees and sixty degrees inclusive.

14. The supply item of claim 9 , wherein the non-volatile memory contains a second array of numbers corresponding to the intensity of the magnetic field radial to the axis of rotation above the shaft at a second plurality of locations each at a second fixed distance from the side surface.

15. The supply item of claim 9 , wherein the non-volatile memory contains a third array of numbers corresponding to the intensity of the magnetic field parallel to the axis of rotation above the shaft along the section of the length of the helical channel at the first plurality of locations.

16. The supply item of claim 9 , wherein the digital signature is generated using asymmetric cryptography.

17. The supply item of claim 9 , wherein the helical channel terminates in a stop.

18. A supply item for an image forming device comprising:
a body;
an auger having a spiral flight having magnetized particles that generate a magnetic field above the spiral flight having a varying intensity, the auger is rotatably mounted to the body; and
a non-volatile memory located on the body containing an array of numbers corresponding to the intensity of the magnetic field above a section of the spiral flight and also containing a digital signature generated from the array of numbers.

19. The supply item of claim 18 , wherein the spiral flight has a helix angle between thirty degrees and sixty degrees inclusive.

20. The supply item of claim 18 , wherein the digital signature is generated using asymmetric cryptography.

Assignees

• Lexmark Int Inc

Inventors

• Ahne Adam Jude
• Dodson Graydon Randall

Classifications

• H04L9/3278

  using physically unclonable functions [PUF] · CPC title

• H04L9/3247

  involving digital signatures · CPC title

• G03G15/0863

  provided with identifying means or means for storing process- or use parameters, e.g. an electronic memory · CPC title

• G06K19/06187

  with magnetically detectable marking · CPC title

• G09C1/00

  Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system (cryptographic typewriters G09C3/00) · CPC title