UTXO Blockchain Account Model Emulation via Persistent Identifier

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Solution Overview

Problem

The UTXO blockchain model lacks the ability to maintain a persistent identifier across transactions, making it difficult to emulate an account model and manage complex smart contracts effectively, as each UTXO is single-use and lacks identifying information about the entity holding it.

Innovation Solution

A computer-implemented method that determines the presence of a unique identifier in both the input and output of a spending transaction, allowing for validation only when the identifier is present in both, thereby enabling the emulation of an account model by linking transactions through a persistent identifier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UTXO model is used with single-use UTXOs and different public keys for each UTXO, then privacy is improved and scalability is improved, but the ability to maintain a record of which UTXOs are held by any given entity deteriorates

Engineering Contradiction:
Improveability to maintain record of entity holdingsVSAvoidcomplexity of tracking UTXO ownership
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an account identifier as an intermediary element that mediates between the UTXO model's privacy requirements and the need for entity tracking. This account identifier is embedded in both the locking script and unlocking script, serving as a persistent link between multiple UTXOs and their owner without exposing private key information. The account identifier acts as a mediator that enables entity identification while maintaining the cryptographic privacy guarantees of the UTXO model.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If each UTXO uses a different public key for locking, then privacy is improved, but the ability to link UTXOs to identify the same entity deteriorates

Engineering Contradiction:
Improveloss of identifying informationVSAvoidability to emulate account model
Core Design Contradiction:
Loss of informationVSAdaptability or versatility

Solution Approach 1:

The patent adds another dimension to the UTXO structure by embedding an account identifier within the locking script and unlocking script. This creates a new layer of information that persists across transactions without compromising the existing public key mechanism. The account identifier dimension enables entity identification while the public key dimension maintains cryptographic security and privacy.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If the UTXO model is used for blockchain transactions, then computational lightweight operations are achieved and scalability is improved, but the difficulty of maintaining persistent entity identification increases

Engineering Contradiction:
Improvetransaction processing speedVSAvoiddifficulty of tracking entity holdings
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by pre-establishing the account identifier linkage between locking and unlocking scripts before the transaction occurs. The account identifier is embedded in advance in the UTXO structure, so that when validation occurs, the connection between entity and UTXO is already established and can be verified without complex tracking operations. This preliminary establishment of the identifier link enables efficient validation while maintaining entity traceability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3907644B1blockchain
Publication Date: 2022.10.05 CAMBRIDGE CRYPTOGRAPHIC LTD
  • EP3907644B1 patent drawingFigure 1a
  • EP3907644B1 patent drawingFigure 1b
  • EP3907644B1 patent drawingFigure 2

AI summary

The present disclosure relates to a computer-implemented method of configuring an Unspent Transaction Output, UTXO, blockchain so that upon a spending transaction being received at a node for validation prior to inclusion in a block of the UTXO blockchain, the node: determines the presence of an identifier in an input of the spending transaction; and validates the spending transaction only when the same identifier is also present in an output of the spending transaction.