IP Library Granted Patent US 12,634,141
Granted Patent B2
US 12,634,141 · App. 18/816,291 · Granted May 19, 2026

Security device computation matching

Inventors: Timothy John Rademacher (Richmond, KY); Jennifer Topmiller Williams (Lexington, KY); Zachary Nathan Fister (Lexington, KY)
Assignee: LEXMARK INTERNATIONAL, INC.
H04L9/3234H04L9/0877H04L9/14H04L2209/12
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Quick Facts
Patent No.
US 12,634,141
App. No.
18/816,291
Granted
May 19, 2026
Kind
B2
Abstract

A method for determining authenticity of a supply item for an imaging system, the method comprising: performing a cryptographic algorithm on the imaging system, starting with a first algorithm input, performing the cryptographic algorithm on the supply item, starting with the first algorithm input, determining authenticity of the supply item based on an imaging system run time and a supply item run time, wherein the imaging system run time is a run time of the cryptographic algorithm on the imaging system from input of the first algorithm input until a result output is generated, and the supply item run time is a run time of the cryptographic algorithm on the supply item from input of the first algorithm input until the result output is generated.

Claims (44)

1 . A method for determining authenticity of a supply item for an imaging device, the method comprising:

performing a cryptographic algorithm on the imaging device, starting with a first algorithm input,

performing the cryptographic algorithm on the supply item, starting with the first algorithm input,

generating parameters for the cryptographic algorithm, the parameters including the first algorithm input to the cryptographic algorithm and including a second parameter, wherein the second parameter is an imaging device run time,

recording an algorithm output as a result output when the cryptographic algorithm has been performed for the imaging device run time on the imaging device,

determining authenticity of the supply item based on the imaging device run time and a supply item run time,

wherein the imaging device run time is a run time of the cryptographic algorithm on the imaging device from input of the first algorithm input until the result output is generated, and the supply item run time is a run time of the cryptographic algorithm on the supply item from input of the first algorithm input until the result output is generated.

2 . The method of claim 1 , wherein the step of determining authenticity comprises determining that the supply item is not authentic when the supply item run time is greater than an upper run time threshold, the upper run time threshold being the imaging device run time plus an upper variance.

3 . The method of claim 2 , wherein the step of determining the authenticity further comprises determining that the supply item is not authentic when supply item run time is less than a lower run time threshold, the lower run time threshold being the imaging device run time minus a lower variance.

4 . The method of claim 3 , wherein the step of determining the authenticity comprises determining that the supply item is authentic when the supply item run time is between the upper run time threshold and the lower run time threshold.

5 . The method of claim 1 , wherein the second parameter comprises matching data indicative of the result output, and wherein when the cryptographic algorithm on the imaging device has produced the result output, the run time of the algorithm is recorded as the imaging device run time.

6 . The method of claim 5 , wherein when an algorithm output on the supply item matches the result output, recording the run time of the algorithm on the supply item as the supply item run time.

7 . The method of claim 1 , the method further comprising:

when the result output is achieved on the imaging device, continuing performance of the cryptographic algorithm on the imaging device until a maximum run time is reached, the maximum run time measured from input of the first algorithm input, and/or

when the result output is achieved on the supply item, continuing performance of the cryptographic algorithm on the supply item until the maximum run time is reached, the maximum run time measured from input of the first algorithm input.

8 . The method of claim 7 , wherein when the maximum run time has been reached on the supply item and the result output has not been generated on the supply item, the supply item sends an error message to the imaging device.

9 . The method of claim 1 , the method further comprising:

generating the imaging device run time and a corresponding imaging device intermediate data from a look-up table,

retrieving, by the supply item, supply item intermediate data from a look-up table on the supply item based on the supply item run time, and

determining the supply item is authentic when the imaging device intermediate data and the supply item intermediate data match.

10 . The method of claim 9 , wherein the imaging device intermediate data and the supply item intermediate data are each a key, seed, salt or algorithm.

11 . The method of claim 1 , wherein the cryptographic algorithm is hardware assisted.

12 . The method of claim 1 , wherein the cryptographic algorithm is a processor-based algorithm.

13 . The method of claim 1 , wherein the method further comprises:

performing a second cryptographic algorithm on the imaging device, starting with a second algorithm input,

performing the second cryptographic algorithm on the supply item, starting with the second algorithm input,

determining the authenticity of the supply item based on a second imaging device run time and a second supply item run time,

wherein the second imaging device run time is a run time of the second cryptographic algorithm on the imaging device from input of the second algorithm input until a second result output is generated, and the second supply item run time is a run time of the second cryptographic algorithm on the supply item from input of the second algorithm input until the second result output is generated.

14 . A method for determining authenticity of a supply item for an imaging device, the method comprising:

performing a cryptographic algorithm on a component of the imaging device, starting with a first algorithm input,

performing the cryptographic algorithm on the supply item, starting with the first algorithm input,

generating parameters for the cryptographic algorithm, the parameters including the first algorithm input to the cryptographic algorithm and including a second parameter, wherein the second parameter is an imaging device run time,

recording an algorithm output as a result output when the cryptographic algorithm has been performed for the imaging device run time on the imaging device,

determining authenticity of the supply item based on the imaging device run time and a supply item run time,

wherein the imaging device run time is a run time of the cryptographic algorithm on the component of the imaging device from input of the first algorithm input until the result output is generated, and the supply item run time is a run time of the cryptographic algorithm on the supply item from input of the first algorithm input until the result output is generated.

15 . An imaging system comprising:

an imaging device; and

a supply item, the supply item being communicatively connectable to the imaging device, wherein the imaging system is configured to:

perform a cryptographic algorithm on the imaging device, starting with a first algorithm input,

perform the cryptographic algorithm on the supply item, starting with the first algorithm input,

generate parameters for the cryptographic algorithm, the parameters including the first algorithm input to the cryptographic algorithm and including a second parameter, wherein the second parameter is an imaging device run time,

recording an algorithm output as a result output when the cryptographic algorithm has been performed for the imaging device run time on the imaging device, and

determine authenticity of the supply item based on the imaging device run time and a supply item run time,

wherein the imaging device run time is a run time of the cryptographic algorithm on the imaging device from input of the first algorithm input until the result output is generated, and the supply item run time is a run time of the cryptographic algorithm on the supply item from input of the first algorithm input until the result output is generated.

Assignments (5)
SECURITY INTEREST Recorded Jan 5, 2026
From: LEXMARK INTERNATIONAL, INC.
To: BANK TRUST COMPANY, NATIONAL ASSOCIATION
Reel/Frame 074202/0192 →
SECURITY INTEREST Recorded Jan 5, 2026
From: LEXMARK INTERNATIONAL, INC.
To: BANK TRUST COMPANY, NATIONAL ASSOCIATION
Reel/Frame 074202/0293 →
SECURITY INTEREST Recorded Sep 23, 2025
From: LEXMARK INTERNATIONAL, INC.
To: CITIBANK, N.A.
Reel/Frame 073007/0118 →
SECURITY INTEREST Recorded Sep 23, 2025
From: LEXMARK INTERNATIONAL, INC.
To: JEFFERIES FINANCE LLC
Reel/Frame 073007/0346 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 27, 2024
From: RADEMACHER, TIMOTHY JOHN; WILLIAMS, JENNIFER TOPMILLER; FISTER, ZACHARY NATHAN
To: LEXMARK INTERNATIONAL, INC.
Reel/Frame 068412/0084 →
Continuity (3)
Continuation 17498230 · Oct 11, 2021
Provisional Application 63163385 · Mar 19, 2021
Related Publication 20240422003A1 · Dec 19, 2024
References Cited (11)
US 6442525B1 · Silverbrook · 2002 [cited by examiner]
US 7228434B2 · Zisowski · 2007 [cited by examiner]
US 7650504B2 · Bodrov · 2010 [cited by examiner]
US 10171804B1 · Wang · 2019 [cited by examiner]
US 10933646B2 · Bonneton · 2021 [cited by examiner]
US 20020154769A1 · Petersen · 2002 [cited by examiner]
US 20050206694A1 · Wadley · 2005 [cited by examiner]
US 20060020936A1 · Wyatt · 2006 [cited by examiner]
US 20180157571A1 · Lünstroth · 2018 [cited by examiner]
US 20210126846A1 · Yi · 2021 [cited by examiner]
US 20220035812A1 · Balaraman · 2022 [cited by examiner]