Printer Chip Authorization Flag for Secure Data Rewriting

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Solution Overview

Problem

Inkjet printer chips are currently limited to single-use due to security concerns, as stored keys can be compromised, reducing their utility and security.

Innovation Solution

Incorporating an authorization flag bit and verification mechanism, allowing the chip to switch between authorized and non-authorized states, enabling data rewriting and prolonging the chip's service life through secure authorization and data management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the key is stored in the chip to guarantee security, then the security of the chip is improved, but the attacker can obtain the key by probing the integrated circuit, thus affecting the security of the chip

Engineering Contradiction:
Improvechip securityVSAvoidkey probing attack
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the key from the chip's permanent storage and stores it temporarily in a register during authorization verification. After verification, the key is discarded and cannot be retrieved. This extraction approach prevents the key from being permanently stored in a form that can be probed and extracted by attackers.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary authorization verification before allowing any data reading or writing operations. The key is loaded into a register and used for verification in advance, and the register is cleared after use. This preliminary action ensures that the key is never present in the chip during normal operation, preventing probing attacks.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the information is written into the printer chip once to guarantee stability and incorrigibility, then the stability of information is improved, but the chip can only be used once and cannot be used repeatedly, thus decreasing the use value of the chip

Engineering Contradiction:
Improveinformation stabilityVSAvoidchip service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent implements dynamic authorization states that can transition between locked and unlocked conditions. The data storage unit has different access modes (read-only, read-write, authorized) that can be changed through the authorization verification process. This dynamic approach allows the chip to maintain information stability when locked while enabling repeated use when authorized.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the authorization parameter (authorized bit) to control data storage unit accessibility. When the authorized bit is 0, the unit is in a locked state with restricted access. When the authorized bit is 1, the unit is in an unlocked state allowing full access. This parameter change enables the chip to transition between single-use and multi-use modes while maintaining information stability.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If the chip data is covered and reread and rewritten to prolong service life, then the service life of the chip is improved, but the stability and reliability of data may be compromised

Engineering Contradiction:
Improvechip service lifeVSAvoiddata stability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by implementing authorization verification before allowing any data writing operations. The system verifies the authorized bit and matching key before permitting data changes, preventing unauthorized or erroneous writes that could compromise data stability. This preliminary check ensures that data can be rewritten during the chip's extended service life without compromising reliability.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3375615B1Printer chip, ink cartridge, and method of allocating data storage to printer chip
Publication Date: 2021.09.29 HANGZHOU CHIPJET TECH CO LTD
  • EP3375615B1 patent drawingFigure 1~2
  • EP3375615B1 patent drawingFigure 3

AI summary

The invention belongs to the field of ink-jet printing, and particularly relates to a printer chip, an ink cartridge and a printer chip storage allocation method. According to the technical scheme, the printer chip comprises a chip control circuit, a data storage unit used for storing data, and a communication unit used for communication with a printer, wherein the data storage unit and the communication unit are electrically connected with the chip control circuit, and the data storage unit comprises an authorization flat bit making the data storage unit in a non-authorized state and an authorized state respectively according to different numerical values. By additionally arranging the authorization flat bit and conducting matched authorization verification, on the basis of guaranteeing data stability and reliability, chip data can be covered, reread and rewritten, normal use is ensured, and the service life of the printer chip is prolonged.