Prepaid Device Debit Value Management via One-Way Function Control
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Solution Overview
Problem
Prepaid value cards for audio/video content face fraudulent reimbursement claims due to the lack of secure mechanisms to verify and manage credit balances, allowing malicious users to exploit unused balances for refunds.
Innovation Solution
A method for managing debit values in prepaid devices using a unique identifier and control value, where one-way functions are applied to modify the control value based on debit changes, ensuring that previous values cannot be reversed, and allowing secure verification of credit balances by an administration center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If reimbursement is possible with value cards, then user attractiveness and satisfaction are improved, but fraudulent claims and financial security deteriorate
Solution Approach 1:
The system performs preliminary verification of the debit value and control value before allowing any reimbursement operation. The administration center calculates the expected control value based on the submitted debit value and compares it with the control value stored in the card before processing the reimbursement, preventing fraudulent claims in advance
Solution Approach 2:
The control value acts as an intermediary verification element between the debit value and the reimbursement process. It serves as a cryptographic proof that links the current debit value to the initial credit value, enabling secure verification without exposing sensitive financial information
2Ease of operation
If credit balance is stored in prepaid device, then content access is enabled, but fraudulent manipulation and verification difficulty increase
Solution Approach 1:
The control value serves as a cryptographic intermediary that proves the authenticity of the debit value without requiring the administration center to trust the card blindly. It enables automatic verification of credit balance integrity
Solution Approach 2:
The patent replaces physical security mechanisms (tamper-proof hardware) with cryptographic verification mechanisms. Instead of relying on hardware security alone, it uses mathematical one-way functions to verify the integrity of the debit value, making fraud detection more reliable
3Reliability
If one-way function is applied to control value, then fraudulent reversal is prevented, but system complexity increases
Solution Approach 1:
The complex cryptographic verification logic is extracted from the prepaid card and placed in the administration center. The card only needs to store and transmit the control value, while the heavy computational burden of verifying one-way functions is performed remotely, keeping the card simple
Solution Approach 2:
The control value is a simple cryptographic intermediary that the card can store and transmit without complex processing. It encapsulates the security logic, allowing the card to remain simple while providing strong security guarantees
Data Source
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AI summary
The goal of the present invention is to secure a prepaid device for access to audio/video content having the possibility of reimbursement of the unused balance upon presentation of the aforementioned device to a control center. This goal is achieved by a method for managing a debit value (V1) in a prepaid device and comprising an identifier (UA) unique to each device and a control value (CT), this method comprising the following steps: -receiving of a request to modify the debit value (V1 ) by an amount (M), -calculating a new debit value (V1') after the modification of the debit value (V1) by the amount (M), - determining a positive whole number or zero of steps (N) according to a function expressing the modification of the new debit value (V1') relative to the debit value (V1), - if the number of steps (N) is non-zero, modifying the control value (CT) by executing at least one one-way function on said control value (CT) a number of times equal to the number of steps (N).