Temporary Card Security Code via Minimal Perfect Hash

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Solution Overview

Problem

Existing card-based transaction systems, particularly in mobile and online transactions, are inadequate in preventing unauthorized use of credit or debit cards, as they lack sufficient security measures to ensure that the cardholder possesses the physical card.

Innovation Solution

A method and system that generate a temporary Card Security Code (CSC) by applying a minimal perfect hash function to the original CSC and a data seed, making it more difficult to obtain fraudulently, and allowing for quick verification by matching the hashed temporary CSC with stored values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional CVV/CSC code is used for card verification, then the transaction process is simple and quick, but the security against fraudulent use is insufficient

Engineering Contradiction:

ImprovesecurityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The verification process is segmented into two distinct phases: enrollment where the minimal perfect hash function is pre-computed and stored, and transaction where the segmented code is quickly verified. This segmentation allows the complex cryptographic operation to be performed only once during enrollment, while maintaining simple and fast verification during transactions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The minimal perfect hash function is applied in advance during the enrollment phase to generate and store the segmented code. This preliminary action ensures that during actual transactions, the system only needs to perform simple verification operations, thus enhancing security without compromising transaction speed.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a temporary CSC generated via hash function is used, then fraud prevention is improved, but the verification process requires additional computational steps

Engineering Contradiction:

Improvefraud preventionVSAvoidverification speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The CSC is segmented into a fixed-length code through the minimal perfect hash function, which enables efficient storage and rapid comparison during verification. The segmentation transforms the verification task into a simple string matching operation that can be performed quickly even with additional security measures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The verification process changes from comparing full-length CSCs to comparing hashed segments of fixed length. This parameter change in the verification approach maintains fraud prevention capabilities while significantly improving verification speed by reducing the computational complexity of the comparison operation.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the original CSC is stored for verification, then verification is straightforward, but the system is vulnerable to database breaches and unauthorized access

Engineering Contradiction:

Improveverification simplicityVSAvoidsecurity vulnerability

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The minimal perfect hash function acts as an intermediary between the original CSC and its stored representation. Instead of storing the original CSC directly, the system stores only the hashed segment, which serves as a secure intermediary that prevents reverse-engineering while enabling verification through the same hash function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces the mechanical approach of storing and comparing original CSCs with a cryptographic hash-based approach. This substitution maintains the simplicity of verification through direct comparison while eliminating the security vulnerability of storing plain-text or easily reversible CSCs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11216817B2Generation and verification of a temporary card security code for use in card based transactions

Publication Date: 2022.01.04 NO COMMON PAYMENT AB

AI summary

The present disclosure presents a method for a card based transaction between a mobile terminal and a service provider system having one or several computer servers. The mobile terminal obtains a CSC from credit card/debit card. The mobile terminal obtains a data seed. The mobile terminal applies a minimal perfect hash function to the CSC as well as the data seed to generate a temporary CSC. The mobile terminal initiates a card based transaction with the service provider system utilizing the generated temporary CSC. The service provider system obtains the temporary CSC and applies a same minimal perfect hash function to the temporary CSC until a match is found between the obtained temporary CSC and one CSC stored at the service provider system. In response to a match the service provider system continues the initiated card based transaction with the mobile terminal.