Personal Code Verification Using Bijective Function Control Values

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Solution Overview

Problem

Existing methods for verifying personal codes on integrated circuit cards are inefficient in terms of energy consumption and vulnerable to power disruptions, particularly in contactless cards, as they require multiple write operations and are susceptible to interruptions in the power supply.

Innovation Solution

A method using a bijective function with a personal code as a specification parameter, where random numbers and their corresponding sequence numbers are stored, allowing for a single write operation to manage verification attempts, ensuring reliable and energy-efficient code verification by comparing control values and random numbers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the remaining number of attempts is decremented after each verification failure, then the security against brute-force attacks is improved, but the energy consumption increases due to multiple write operations in non-volatile memory

Engineering Contradiction:
ImprovesecurityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing control values corresponding to all possible personal codes before verification begins. During verification, the system only needs to retrieve and compare these pre-computed values with the transformed submitted code, eliminating the need for decrementing attempts during the verification process itself. This approach maintains security while reducing energy consumption by avoiding repeated write operations.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the maximum possible number of attempts is stored in memory after each successful verification, then the reliability of attempt tracking is improved, but the energy consumption increases and the system becomes vulnerable to power interruption

Engineering Contradiction:
Improveattempt tracking reliabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary action by pre-computing and storing control values for all possible personal codes before verification begins. During verification, the system retrieves the appropriate control value based on the submitted code and compares it with a transformed version of the submitted code. This eliminates the need for write operations during verification, reducing energy consumption and vulnerability to power interruptions while maintaining reliable attempt tracking.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a copy of the verification logic by pre-computing control values for all possible personal codes and storing them in memory. Instead of performing complex calculations or write operations during each verification attempt, the system simply retrieves the pre-computed control value and compares it with the transformed submitted code. This copying approach reduces energy consumption and eliminates vulnerability to power interruptions during the critical verification process.

Inventive Principle:
Principle #26Copying

3Measurement precision

If two write operations are performed in non-volatile memory for each verification cycle, then the accuracy of attempt counting is improved, but the device complexity and energy consumption increase

Engineering Contradiction:
Improveattempt counting accuracyVSAvoidverification process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating control values for all possible personal codes before verification begins. During verification, the system only needs to retrieve the appropriate control value and compare it with the transformed submitted code, eliminating the need for complex write operations during each verification cycle. This maintains accurate attempt counting while reducing device complexity and energy consumption.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2245604B1Method for verifying a code
Publication Date: 2019.05.29 IDEMIA IDENTITY & SECURITY FRANCE SAS
  • EP2245604B1 patent drawingFigure 1

AI summary

The invention relates to a method for verifying a personal code using a memory containing random numbers each associated with an order number, results of a calculation made on each random number using a bijective function and the personal code as a bijective function specification parameter, a maximum possible number of verification attempts, a theoretical remaining number of verification attempts, and a control value associated with an order number.