Transponder Key Delay for RFID Privacy

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Solution Overview

Problem

RFID tags face privacy issues due to unauthorized reading and tracking, with existing solutions either limiting their functionality or requiring extensive administration, and current cryptographic techniques reduce response rates, limiting their applicability.

Innovation Solution

A transponder system that stores encrypted information and its associated key, where the key is sent slower than the encrypted information in response to queries, using key delay or response rate limiting means, and implements semantically secure encryption with a random number generator to prevent linking and tracking, while allowing fast data transmission of encrypted information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the transponder transmits the key at the same speed as the encrypted information, then the processing speed is maximized, but privacy security deteriorates due to unauthorized reading and tracking

Engineering Contradiction:
Improveprocessing speedVSAvoidprivacy risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the data transmission into two distinct parts: encrypted information transmitted at high speed and the decryption key transmitted at a deliberately reduced speed. This segmentation allows the system to maintain high processing speed for the main data while protecting privacy through slow key transmission, directly resolving the contradiction between productivity and privacy security.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism (response rate limiting means) that mediates the transmission speed of the key. This intermediary component acts as a speed governor, allowing the encrypted information to flow rapidly while restraining the key transmission to a slower pace, thus enabling both high processing speed and enhanced privacy protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the transponder transmits the key slower than the encrypted information, then privacy security is improved, but processing speed deteriorates

Engineering Contradiction:
Improveprivacy riskVSAvoidprocessing speed
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies local quality by assigning different transmission speeds to different parts of the data structure. The encrypted information enjoys high-speed transmission for optimal processing speed, while the key portion is deliberately transmitted slower for enhanced privacy security. This localized differentiation resolves the contradiction by optimizing each component's transmission speed according to its specific security requirements.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If semantically secure encryption is implemented, then tracking prevention is improved, but response rate deteriorates due to calculation time

Engineering Contradiction:
Improvetracking preventionVSAvoidresponse rate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing the encrypted information before transmission. The semantically secure encryption is performed in advance during the tagging process, allowing the encrypted data to be stored in the transponder's memory. During querying, the pre-encrypted information can be transmitted rapidly without real-time calculation, thus maintaining high response rate while ensuring tracking prevention through semantically secure encryption.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP1894148B1Transponder system for transmitting key-encrypted information and associated keys
Publication Date: 2011.04.20 NXP BV
  • EP1894148B1 patent drawingFigure 1
  • EP1894148B1 patent drawingFigure 2~3
  • EP1894148B1 patent drawingFigure 4

AI summary

A transponder (1) comprises at least one memory (MEMl, MEM2) for storing encrypted information (E_ k(EPC, PI)) that has been encrypted by use of a key (k) and for storing the key (k) associated with the encrypted information (E_ k(EPC, PI)). The transponder (1) is adapted to send the key (k) slower response than the encrypted information (E_ k(EPC, PI)) in response to queries of a reading device (2), which is preferably done by delaying the transmission of the key (k) or by limiting the response rate at which the key (k) is transmitted. In particular the invention is related to RFID systems.