NFC Payment Authentication Triplet for Fraud Prevention
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Solution Overview
Problem
In NFC-based payment transactions, unsecured merchant terminals can be compromised by malicious software, leading to fraudulent activities where the user's device is forced to sign arbitrary messages, resulting in unauthorized transactions.
Innovation Solution
A method involving the creation of an authentication triplet, comprising an authentication code and two signature components, is implemented. The user device computes these components using a hash function and private keys, and transmits them to the merchant terminal for blind verification, ensuring the message's validity without revealing the message itself.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If contactless payment is implemented using NFC protocols, then payment convenience is improved, but security against fraudulent transactions deteriorates
Solution Approach 1:
The authentication process is segmented into multiple independent components: a challenge generated by the terminal, a response computed by the device using private keys, and verification performed by the terminal. This segmentation ensures that even if one component is compromised, the overall authentication remains secure.
Solution Approach 2:
The terminal generates a random challenge message before the payment transaction and transmits it to the device. This preliminary action ensures that the device must compute the response based on this specific challenge, preventing replay attacks and ensuring the response is unique to this transaction.
2Adaptability or versatility
If the merchant terminal is a third-party device, then payment versatility is improved, but security reliability deteriorates
Solution Approach 1:
The authentication protocol acts as an intermediary mechanism between the user device and the merchant terminal. It ensures that even though the terminal is a third-party device with potentially untrusted applications, the cryptographic challenge-response mechanism guarantees that only authorized transactions can be completed.
Solution Approach 2:
The user device performs self-verification by computing the response using its private keys and verifying that the terminal can correctly validate it. This self-service approach allows the device to ensure transaction authenticity without relying on the security of the terminal's operating system or installed applications.
3Productivity
If the user device signs arbitrary messages, then transaction processing speed is improved, but security against misuse deteriorates
Solution Approach 1:
The protocol changes the parameter being signed from static data to a dynamic challenge message generated by the terminal. This ensures that each transaction requires signing a unique message, preventing fraudulent reuse of signatures while maintaining fast processing through efficient cryptographic operations.
Data Source
AI summary
A method for authenticating data, implemented during a payment transaction between a merchant's communications terminal and a user device of the type including authentication by the communications terminal of at least one message generated by the user device, by using near field communications wireless data. The method includes the following acts by the user's device: obtaining an authentication code from the message, a piece of random data and a hash function; obtaining a first signature component from the message, the random piece of data, a public key of the communications terminal, a first private key of the user device and the authentication code; obtaining a second signature component from the message, the random piece of data, the public key of the communications terminal, a second private key of the user device and the authentication code; and transmitting the authentication code and of the two signature components to the communications terminal.