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As described in the project proposal, a number of Core Operator primitives for DLT interoperability have been identified.  They are:the first step we have identified in the integration process is the building of a Core Operators module (let's call it COPM) that directly acts on a network's (or system's) ledger, which can be seen at the right end of the above diagram. (Note: because different ledgers are built on different DLTs, Cacti will support an extensible suite of COPMs, one for each DLT.)

In this project, we need to do the following:

• Design a generic structure and interface (API) for the COPM that is portable across DLTs (while being implemented in DLT-specific ways for each ledger type.)
  
• Identify a list of Core Operator primitives to implement. Thus far, we have identified a limited set of such operators, which in some combinations can fulfil the three canonical DLT interoperability use cases: data sharing, asset exchange, and asset transfer. (Note: this set is meant to be extensible, to accommodate more operators if we discover functions that are not covered by the below list)
  • lockAsset
  • pledgeAsset
  • claimAsset
  • generateProof
  • verifyProof
• Noop

All three DLT interoperability use cases – data sharing, asset transfer, and asset swap – are a combination of the above primitives. 

• • accessControl
  • noop (this is a passthrough option, for Cacti modules and connectors that do not need to invoke any of the above operators)
• Implement a COPM for Hyperledger Fabric
  • On a best effort basis, implement a COPM (in part or whole) for Corda
  • On a best effort basis, implement a COPM (in part or whole)  for Besu/Ethereum
• Sketch out a template for porting to arbitrary DLTs and write documentation (this may end up being part of the Cacti whitepaper)
• Write scripts to deploy COPMs on a given network
• Refactor existing Cacti packages (select a few) to invoke the appropriate COPM
• Pick some end-to-end examples to showcase (this should cover existing Cactus examples, existing Weaver examples on data sharing, asset exchange, and asset transfer)

Preliminary work:

• Test and evaluate Cactus setups and examples using instructions in the documentation.
  
• Test and evaluate Weaver setups and samples using instructions in the documentation.
  
• Document bugs, required upgrades in software, instruction typos, and identify automation scripts that can help make tooling and CI more efficient.
  
• Expose Weaver modules and libraries through symlinks in the packages  folder to simplify the integration process.

(The intention of this project is to unify multiple interoperability frameworks by creating a reusable set of operators so that the existing frameworks can be migrated to them.)

Key Deliverables

•  

  Cacti Core Operators Module , with grpc or socket IO external interface, and REST API integrated into the Cacti Client API. These operators are to be implemented in:

  •  corda
  •  hyperledger fabric
  •  hyperledger besu

  (COPM) design: functions (see the list in the project scope above) and API

  •  

    API should be RESTful, built on gRPC or socket.IO, designed to be integrated with the Cacti Client API and invoked by Cacti Connectors

•  

  Implementation of COPM:

  •  Hyperledger Fabric: (required: all functions and API)
  •  R3 Corda: (best effort: some functions and associated API)
  •  Hyperledger Besu: (best effort: some functions and associated API)
•  Selection of use cases (examples) for end-to-end testing: both Cactus (Node Server) and Weaver (Relay) modes
  •  Weaver data sharing using test networks (minimum required)
  •  Other Weaver use cases (asset exchange, asset transfer) (best effort)
  •  Cactus examples: TBD
•  CI-automated testing of Core Operator Module COPM for all combinations
•  

  Documentation of the above, including API documentation and getting started guide

•  RFCs updated

• :

  •  

    Updates to architecture, vision, design methodology (as required)

  •  

    Tutorials for running with Cacti samples

  •  FAQs (best effort) 
  •  

    Suggestive instructions for adaptation to users' scenarios (best effort)
    

•  Updated RFCs: COPM design and API specifications
  

Optional Deliverables

•  Unified cacti Cacti CI github GitHub workflows
•  Weaver tests run-able in local environment via docker
•  Weaver test examples updated to use core operators
•  Dockerize Weaver test tooling for easy setup (equivalent of a the fabric-tools container offered by Fabric)
•  Cactus REST APIs updated to use core operators
•  Redundant code identified and removed
•  Implementation of Core Operator Module in other DLTsDLTs other than Fabric, Corda, and Besu

Timeline