Card Reader Key Exchange for Secure Terminal Data Transmission

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Solution Overview

Problem

The transmission of personal identification elements, such as PIN codes, entered on a merchant's mobile terminal to a card reader is insecure, posing a weak link in the payment transaction process, as the terminal often lacks the necessary security features to ensure data integrity.

Innovation Solution

A method involving a card reader and an authentication server shares an authentic encryption key to securely exchange encryption keys with the terminal, using asymmetric encryption protocols and potentially a Diffie-Hellman algorithm, ensuring that only the intended public keys are used for data encryption, thereby securing the transmission of personal identification data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data transmission is performed between terminal and card reader without additional security protocols, then communication simplicity is maintained, but security of personal identification data is compromised

Engineering Contradiction:
Improvesecurity of personal identification dataVSAvoidcomplexity of key exchange protocol
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an authentication server as an intermediary between the terminal and card reader. This server facilitates secure key exchange by mediating the authentication process, allowing terminals without security elements to communicate securely with card readers through a trusted third party that manages the security infrastructure centrally

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If asymmetric encryption protocols are implemented for secure key exchange, then security of data transmission is improved, but computational overhead and processing time increase

Engineering Contradiction:
Improveintegrity of payment transactionVSAvoidtime for key exchange process
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary authentication and key exchange actions before the actual payment transaction. The terminal and card reader establish secure communication channels in advance through the authentication server, so that when the actual transaction occurs, the security framework is already in place and ready for rapid operation

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3665605B1Methods and devices for the secure transmission of data between a terminal and a card reader, and corresponding computer program products
Publication Date: 2025.09.10 BANKS & ACQUIRERS INT HLDG SAS
  • EP3665605B1 patent drawingFigure 1~5
  • EP3665605B1 patent drawingFigure 2
  • EP3665605B1 patent drawingFigure 3

AI summary

The invention relates to a method for securely receiving, in a card reader, at least one data item entered into a terminal connected to the card reader. The method comprises the following steps, performed by the card reader: - obtaining (E200) an encryption key from the card reader, called the reader key; - encrypting (E210) the reader key, using a genuine key shared between the card reader and an authentication server, issuing an encrypted reader key; - sending (E220), to the authentication server, the encrypted reader key for transmission to the terminal; - receiving (E230) an encrypted terminal key sent by the authentication server resulting from an encryption of a terminal key, obtained by the authentication server, using the genuine key; and - receiving (E250) at least one encrypted data item sent by the terminal, resulting from an encryption using at least the reader key and the terminal key of the at least one data item.