Smart-Contract Private Blockchain Transfers Against Double Spending

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Solution Overview

Problem

Existing blockchain technologies lack the ability to facilitate secure, private transactions between participants while preventing double spending and ensuring compliance with regulations, as they often expose transaction data to unauthorized entities and allow for potential fraud.

Innovation Solution

A system utilizing smart contracts and a central authority to manage private transactions within privacy groups, where a first participant's initiate message is processed through a smart contract, verified by a central authority, and only approved transactions are added to the blockchain, ensuring privacy and preventing double spending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If transactions are made private in blockchain privacy groups, then participant anonymity and transaction privacy are improved, but the risk of double spending increases and compliance monitoring becomes difficult

Engineering Contradiction:
Improvetransaction privacyVSAvoiddouble spend prevention
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

A central authority acts as an intermediary between participants in privacy groups, receiving event messages from smart contracts and issuing response messages that confirm transaction validity. This mediator enables private transactions while preventing double spending by maintaining authoritative control over currency balances and transaction approval, thus resolving the contradiction between privacy and reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a central authority is introduced to prevent double spending in private transactions, then transaction security and compliance are improved, but the decentralization and anonymity benefits of blockchain are reduced

Engineering Contradiction:
Improvetransaction securityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system segments functionality between distributed blockchain nodes that execute smart contracts for private transactions and a centralized authority that handles balance verification and approval. This segmentation allows the majority of transaction processing to remain decentralized and private while only critical security functions are centralized, thus improving security without completely sacrificing decentralization.

Inventive Principle:
Principle #1Segmentation

3Loss of information

If all transaction data is visible to authorized participants, then transparency and auditability are improved, but participant privacy and sensitivity of transaction information are compromised

Engineering Contradiction:
Improveinformation transparencyVSAvoidprivacy exposure
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The system implements local quality by making transaction visibility dependent on the specific participant's authorization level and relationship to the transaction. Participants see only transactions relevant to them (involving their wallet or privacy group), while the central authority sees all transactions for compliance monitoring. This selective visibility resolves the contradiction between transparency and privacy.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4427159B1Method and system for private transaction processing
Publication Date: 2025.09.17 MASTERCARD INT INC
  • EP4427159B1 patent drawingFigure 1
  • EP4427159B1 patent drawingFigure 2
  • EP4427159B1 patent drawingFigure 3

AI summary

A method for facilitating secure private. -transfers in a blockchain includes: receiving an initiate message from a device for a proposed private transfer including a private group identifier, entity identifier, and transfer amount; executing a smart contract using the initiate message as input resulting in transmitting an event message to a central authority system including the -entity identifier and transfer amount; receiving a response message from the central authority- system including an indication of approval or rejection of the proposed private transfer; and executing the smart contract using the response message as input resulting in (i) adding a.private: blockchain transaction for transfer of the transfer amount from a first blockchain wallet associated with the entity identifier to a second blockchain wallet in a private group associated with the private group identifier if the response message includes an indication of approval, or (ii) declining the proposed private transfer.