Imaging Device Supply Chip Secure Initialization

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Solution Overview

Problem

There is a need for secure communication and trust establishment between supply items, such as toner cartridges, and imaging devices, to manage the usage of consumables like toner, ensuring authorized and metered usage while preventing counterfeiting and ensuring secure communication protocols.

Innovation Solution

A chip with memory storing quanta indicating allowed usage and a multiplier correlating quanta to toner mass is used, with the imaging device loading these values via a certificate, enabling secure communication and mutual authentication through encrypted and unencrypted firmware versions and device certificates, utilizing an I2C communications bus for secure data exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encrypted and unencrypted firmware versions and certificates are exchanged during initialization, then trust establishment and security verification are improved, but communication complexity and initialization time increase

Engineering Contradiction:
Improvetrust establishmentVSAvoidcommunication complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs security verification and trust establishment during the initialization phase before normal operation begins. Firmware versions and certificates are exchanged and verified in advance, ensuring security is established upfront rather than during ongoing operations, thus preventing security issues during active use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses certificates as an intermediary mechanism to establish trust between the imaging device and supply item. The certificates act as a mediator that carries authentication information, allowing the devices to verify each other's identity and firmware integrity without requiring direct complex authentication protocols during operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If quanta and multiplier values are stored in chip memory with certificate, then usage control and anti-counterfeiting are improved, but memory requirements and chip complexity increase

Engineering Contradiction:
Improveusage controlVSAvoidchip complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the security-critical data (quanta, multiplier, certificate) into a separate chip component that can be independently manufactured and secured. This separation allows the main imaging device to remain simpler while the chip handles the complex security functions, dividing the system into specialized components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses quanta as a parameter to control usage, where the allowed number of imaging operations is defined by the quanta value stored in the chip. This parameter-based control mechanism provides flexible usage management without requiring complex hardware controls, as the software/firmware can enforce limits based on the stored parameter values.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If both encrypted and unencrypted firmware instances are provided for comparison, then security verification is improved, but data transmission volume and communication time increase

Engineering Contradiction:
Improvesecurity verificationVSAvoiddata transmission volume
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent provides both encrypted and unencrypted firmware instances, which means transmitting more data than strictly minimum required. However, this excessive action enables comprehensive security verification by allowing the device to compare the decrypted encrypted instance with the unencrypted instance, ensuring firmware integrity and authenticity.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent creates a copy of the firmware in encrypted form and transmits both the original unencrypted version and the encrypted copy. This copying approach allows verification by decryption and comparison, ensuring that the firmware has not been tampered with while maintaining the ability to use the unencrypted version for operation.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3776357B1Chip and supply item for imaging device, including communication
Publication Date: 2024.05.22 LEXMARK INTERNATIONAL INC
  • EP3776357B1 patent drawingFigure 1
  • EP3776357B1 patent drawingFigure 2
  • EP3776357B1 patent drawingFigure 3A

AI summary

A supply item has toner for use in an imaging device. A chip has memory storing quanta indicating allowed usage of the supply item over its lifetime and a multiplier correlating the quanta to toner mass. The imaging device requires quanta to conduct imaging operations and loads the quanta and multiplier by way of a certificate stored in the memory. The imaging device retrieves quanta from the chip over time and both devices keep tally. Initialization between the supply item and imaging device includes providing encrypted and unencrypted instances of firmware versions and certificates from the supply item that the imaging device can compare for security. Alternatively, the supply item defines a fuser assembly, imaging unit, intermediate transfer member, or other component installed for use in the imaging device.