Permissioned Blockchain Layer 2 Bridge for Off-Chain Cryptocurrency Payments

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Solution Overview

Problem

Private blockchains lack a default currency, making it difficult to ensure their worth and facilitating transactions using existing cryptocurrencies.

Innovation Solution

A method for securing cryptocurrency transactions on a permissioned blockchain by receiving a join request, verifying the execution of an enroll transaction, crediting an account with the cryptocurrency balance, and transferring the balance to another account on the private blockchain, utilizing Byzantine Fault Tolerant (BFT) proofs for security and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a permissioned blockchain is created, then transaction efficiency and security are improved, but the lack of a default currency reduces its versatility and value

Engineering Contradiction:
Improvetransaction securityVSAvoidcurrency compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a bridge smart contract deployed on the public blockchain as an intermediary between the permissioned and permissionless blockchains. This bridge contract holds cryptocurrency assets in escrow and enables their representation on the private blockchain through verified enrollment transactions, allowing the permissioned blockchain to use external cryptocurrencies without compromising its security model

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system segments the cryptocurrency asset representation into two distinct components: the actual cryptocurrency assets held on the public blockchain and the corresponding tokens or representations on the permissioned blockchain. This segmentation allows each blockchain to operate independently with its own security model while maintaining asset portability across chains

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If transactions are executed on a public blockchain, then cryptocurrency availability is improved, but transaction speed and cost increase

Engineering Contradiction:
Improvecryptocurrency availabilityVSAvoidtransaction speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent moves cryptocurrency transactions from the single dimension of public blockchain execution to a two-dimensional architecture where enrollment and verification occur on the public blockchain but subsequent transactions execute on the permissioned blockchain. This dimensional shift enables transactions to leverage the availability of public cryptocurrencies while achieving the speed and cost benefits of private blockchain execution

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

3Adaptability or versatility

If cryptocurrency assets are transferred between blockchains, then interoperability is improved, but security verification complexity increases

Engineering Contradiction:
Improveinter-blockchain interoperabilityVSAvoidverification complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bridge smart contract on the public blockchain performs self-service verification by automatically monitoring and verifying enrollment transactions. The contract autonomously updates its internal state to reflect enrolled assets and generates verification data that the permissioned blockchain can trust without requiring complex external validation mechanisms

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements feedback loops where the permissioned blockchain receives verification data from the public blockchain bridge contract, and the bridge contract receives enrollment transaction data from the permissioned blockchain. This bidirectional feedback mechanism maintains consistent state across both chains while simplifying verification through automated information exchange

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4134855B1Blockchain based layer 2 application for delegated off-chain payments using cryptocurrencies
Publication Date: 2025.05.21 NEC CORP
  • EP4134855B1 patent drawingFigure 1
  • EP4134855B1 patent drawingFigure 2
  • EP4134855B1 patent drawingFigure 3

AI summary

A method for securing a cryptocurrency transaction on a permissioned blockchain, which involves cryptocurrencies of a permissionless public blockchain, includes receiving a join request including a transaction identification. The transaction identification identifies an enroll transaction involving a public smart contract deployed on the permissionless public blockchain, the enroll transaction identifying a permissioned blockchain public key being valid on the permissioned blockchain and transferring a cryptocurrency balance to the public smart contract. The method further includes verifying that the enroll transaction was properly executed, crediting an account corresponding to the permissioned blockchain public key with the cryptocurrency balance, and receiving a send request identifying a second cryptocurrency balance and a second permissioned blockchain public key being valid on the permissioned blockchain. The method also includes transferring the second cryptocurrency balance from the permissioned blockchain public key to the second permissioned blockchain public key.