Numerical Control Data Protection via Table Hashing

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Solution Overview

Problem

Existing methods for protecting data in numerical control systems for machine tools from accidental or unauthorized changes are either complex or only detect changes without preventing them.

Innovation Solution

A method that uses a security column in tables to store hash values of passwords, requiring re-entry and verification of the password for write access, and generates additional hash values for each row to detect manipulation, while using placeholders to indicate protected rows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a comprehensive database-driven access rights management system is used to regulate read and write access, then data protection against unauthorized changes is improved, but device complexity becomes too high for numerical control applications

Engineering Contradiction:
Improvedata protectionVSAvoidaccess rights management system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the data table into multiple rows, with each row independently protectable by its own password. This segmentation allows granular protection of specific data rows without requiring a comprehensive access rights management system for the entire database, thus reducing overall system complexity while maintaining data protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent pre-calculates and stores hash values of passwords in the table before actual data access occurs. This preliminary action eliminates the need for complex real-time authentication systems, as the verification can be performed simply by comparing hash values when data is accessed or modified.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If hash values are stored in the table for protection, then data integrity detection is improved, but the ability to prevent unauthorized changes is insufficient

Engineering Contradiction:
Improvechange detectionVSAvoidunauthorized change prevention
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

Instead of storing passwords directly and verifying them through complex authentication, the patent inverts the approach by storing hash values of passwords and using these hashes as the protective mechanism itself. The password becomes secondary, and the hash value stored in the table becomes the primary verification element, simplifying both prevention and detection.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces hash values as an intermediary between the password and the data protection mechanism. The hash value serves as a mediator that transforms the password into a form that can be stored and verified without exposing the original password, thereby enabling both prevention and detection of unauthorized changes.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If passwords are stored directly in the table for protection, then ease of operation is improved, but security against unauthorized access deteriorates

Engineering Contradiction:
Improvepassword managementVSAvoidunauthorized password access
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical approach of storing plain-text passwords with a cryptographic hash function. Instead of directly storing and comparing password strings, the system transforms passwords into hash values, providing security while maintaining operational simplicity through automated hash comparison.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2983100B1Protecting data of a numerical control system
Publication Date: 2019.07.10 DR JOHANNES HEIDENHAIN GMBH
  • EP2983100B1 patent drawingFigure 1~2

AI summary

A method is described for protecting data (a1 - h4) of a numerical control for machine tools stored in a table (T) against unauthorized or accidental changes. According to this method, information (H1) about the protection of the data (a1 - h4) contained in a selected row (N) is stored in a security column (S) of the table (T). The method comprises the steps of initially entering a password into a current cell (X) of the security column (S) located in the selected row (N), calculating a new hash value (H2) of the password, and storing this hash value in the current cell (X) as a stored hash value (H1). Upon subsequent write access to such protected data,In the selected row (N), the password is re-entered into the current cell (X) of the security column (N), and the new hash value (H2) of the re-entered password is calculated and compared with the hash value (H1) stored in the current cell (X) of the security column (S). Write access to the selected row (N) is only granted if the new hash value (H2) and the stored hash value (H1) match.