AID Applet Command Routing for Memory Reduction

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Solution Overview

Problem

Resource-constrained card devices, such as those using Java Card technology, face inefficiencies in memory usage due to the need for multiple applet instances for different conditions like country and contact type, leading to increased memory requirements.

Innovation Solution

A card device with a special AID applet instance that processes commands and forwards them to the appropriate functional applet using a transfer table, allowing a single instance of the functional applet to operate under various conditions without creating multiple instances, thereby reducing memory usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple applet instances are created for different conditions (country, contact type), then the card device can function under various conditions, but memory usage increases

Engineering Contradiction:
Improvefunctionality under different conditionsVSAvoidmemory usage
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

A single applet instance is designed to handle multiple conditions (different countries, contact types) by incorporating conditional logic and configuration data. The applet can adapt its behavior based on the execution conditions rather than requiring separate instances for each condition, thus achieving multi-functionality with a single instance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Multiple condition-specific applet functionalities are merged into a single unified applet instance. The applet contains internal logic to distinguish between different conditions (country codes, contact types) and executes appropriate functions accordingly, combining what would traditionally require separate instances into one consolidated entity.

Inventive Principle:
Principle #5Merging (Combining)

2Quantity of substance

If a single applet instance handles multiple conditions, then memory usage is reduced, but the complexity of command routing increases

Engineering Contradiction:
Improvememory usageVSAvoidcommand routing complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The command routing logic is segmented into distinct evaluation steps: first checking country code conditions, then contact type conditions, and finally executing the appropriate function. This segmentation of the decision-making process into discrete, manageable steps reduces the perceived complexity compared to a monolithic routing approach.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The applet performs preliminary evaluation of execution conditions (country code, contact type) before executing the main function. By pre-evaluating these conditions and determining the appropriate action in advance, the routing logic becomes more structured and easier to manage, reducing overall system complexity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3593310B1Card device having applets and transfer of apdus to applets
Publication Date: 2023.08.09 GIESECKE & DEVRIENT EPAYMENTS GMBH
  • EP3593310B1 patent drawingFigure 1~2

AI summary

The invention provides a card device having functional applets, an AID applet, and a transfer table that forwards commands addressed to the AID applet to the functional applets.