Decentralized Blockchain Transaction Mixing via Smart Contracts

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Solution Overview

Problem

Existing blockchain transaction mixing solutions require a centralized service provider, compromising the decentralized architecture, security, and confidentiality of transactions, as they introduce additional overhead and risk of asset theft or exposure of user links.

Innovation Solution

A decentralized system for blockchain transaction mixing that allows users to construct and execute transaction chains with randomly chosen participants, using commitment and execution transactions to secure and obscure the transfer of resources without a central mixing service provider, employing protocols like Group Random Exchange (GRE) that utilize payment channels and refund transactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a centralized service provider is used for transaction mixing, then transaction anonymity is improved, but system security and decentralization are worsened

Engineering Contradiction:

Improvetransaction traceabilityVSAvoidsystem security

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The system enables users to perform transaction mixing themselves through automated smart contract execution on the blockchain, eliminating the need for centralized service providers. Users deploy mixing contracts that automatically facilitate anonymous transactions without requiring trust in third parties, thus maintaining anonymity while improving security and decentralization.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent introduces blockchain-based smart contracts as neutral intermediaries that automatically execute transaction mixing logic. These contracts act as trustless mediators that facilitate anonymous transactions between users without requiring centralized control, resolving the contradiction by providing automated, transparent, and secure mixing services through code rather than centralized entities.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a centralized service provider is used for transaction mixing, then transaction mixing functionality is improved, but device complexity and overhead are worsened

Engineering Contradiction:

Improvetransaction mixing capabilityVSAvoidsystem overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates universal mixing smart contracts that can handle multiple transaction types and serve various users through a single decentralized infrastructure. These contracts provide versatile transaction mixing capabilities across different blockchain networks and use cases without requiring separate centralized services for each function, reducing overall system complexity while maintaining adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If a centralized service provider is used for transaction mixing, then transaction mixing is achieved, but confidentiality and anti-theft protection are worsened

Engineering Contradiction:

Improvetransaction mixing serviceVSAvoidasset theft risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Users maintain direct control of their funds through self-custody wallets and private keys throughout the mixing process. The decentralized smart contracts enable users to autonomously execute mixing operations without transferring custody to third parties, eliminating asset theft risks associated with centralized providers while maintaining full mixing functionality.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system incorporates built-in security mechanisms within the smart contracts that prevent unauthorized access and fund misappropriation before they can occur. These preventive measures include automated validation logic, time-locked transactions, and cryptographic safeguards that proactively protect user assets from theft while enabling transaction mixing services.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentEP4207024B1Computer-implemented system and method for performing transaction mixing on a blockchain

Publication Date: 2024.11.20 NCHAIN LICENSING AG

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AI summary

A method and system for performing transaction mixing between a plurality of users on a blockchain is provided. The blockchain may be, for example, the Bitcoin blockchain. The system is configured to carry out the steps of: (i) preparing a first commitment transaction arranged to transmit control of a resource from a source address of a first user to a receiving address of a second user; (ii) preparing a second commitment transaction arranged to transmit control of a resource from a source address of the second user to a receiving address of a further user; (iii) preparing a further commitment transaction arranged to transmit control of a resource from a source address of the further user to either: (a) a receiving address of the first user; or (b) a receiving address of a yet further user and repeating step (iii) until option (a) is performed to complete a transaction chain; and (iv) executing the transaction chain. The users are randomly chosen from the plurality.