NFC Secure Element Encryption for Mobile Transaction Data

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Solution Overview

Problem

Existing NFC transactions lack reliable protection for secret and sensitive data exchanged between electronic device modules, compromising user confidentiality and anonymity.

Innovation Solution

A method for NFC transactions involving a mobile terminal with a processor, a near-field communication module, and a secure element, where the secure element encrypts and decrypts data, ensuring only authorized applications access sensitive information by requesting and providing encryption/decryption keys based on predefined authorization rules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If secret data and sensitive data are exchanged between modules without protection, then NFC transaction functionality is enabled, but data security and user confidentiality are compromised

Engineering Contradiction:
Improvedata securityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system is segmented into distinct functional modules: a secure element for key storage and cryptographic operations, an NFC module for communication, and an application layer for business logic. This segmentation isolates sensitive operations to the secure element, protecting data without requiring the entire system to be complex.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The secure element acts as an intermediary between the NFC module and the application. It receives encrypted data from the NFC module, performs decryption using stored keys, and returns plaintext only to authorized applications. This intermediary role protects data while simplifying the overall system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If encryption and decryption operations are implemented, then data confidentiality is protected, but processing time and operational complexity increase

Engineering Contradiction:
Improvedata confidentialityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Encryption keys are pre-loaded into the secure element during device manufacturing or initial setup. This preliminary action eliminates the need for key generation and storage operations during actual NFC transactions, reducing processing time while maintaining strong encryption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The secure element autonomously performs encryption and decryption operations using its internal keys without requiring external intervention. This self-service capability streamlines the transaction process, as the secure element handles cryptographic operations in-place without requiring data to be transferred to other processors for decryption.

Inventive Principle:
Principle #25Self-service

3Reliability

If authorization checks are performed before decryption, then unauthorized access is prevented, but transaction speed is reduced

Engineering Contradiction:
Improveaccess controlVSAvoidtransaction speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The secure element maintains a pre-configured authorization list of trusted applications during initialization. Before performing decryption, it quickly checks whether the requesting application is in this pre-approved list. This preliminary authorization setup enables rapid access control decisions without complex real-time verification, maintaining both security and transaction speed.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4198791B1NFC transaction
Publication Date: 2024.06.26 STMICROELECTRONICS (ROUSSET) SAS
  • EP4198791B1 patent drawingFigure 1
  • EP4198791B1 patent drawingFigure 2
  • EP4198791B1 patent drawingFigure 3

AI summary

This description relates to a method for carrying out an NFC transaction between a mobile terminal and a remote module, said terminal comprising a processor (2011) hosting an application (2014) establishing the NFC transaction, a near field communication module (2013), and a secure element (2012) separate from the processor (2011), the method comprising at least the following successive steps: (a) said near field communication module (2013) sends, to said first application (2014), first data sent by the remote module (203) and encrypted by said secure element (2012); and (b) said first application (2014) requests said secure element (2012) to decrypt said first data.