Confidentiality and Data Integrity in Consortium Blockchain Applications for Model Based Systems Engineering

Blockchain is a decentralized ledger technology with many unique desirable properties such as immutability, security, trustworthiness, traceability, decentralized authority, fault tolerance, and smart contracts (SC). It has the potential of serving as the foundational technology for building effective data repositories for demanding applications. In consortium Model Based Systems Engineering (MBSE) projects, a single Authoritative Source of Truth (AST) repository of digitalized models is essential for a team of collaborators with semi-trust between each other. Two major challenges in building blockchain-based solutions for MBSE are confidentiality and data integrity. In confidentially, strong, nuanced security rules must be specified and assured to preserve privacy and intellectual property between participating organizations. Unlike cryptocurrency and non-fungible assets, MBSE models have rich internal data structures, relationships, and constraints that need to be captured and assured. Based on the design and implementation of a minimum viable product's blockchain prototyping project on a consortium aerospace MBSE application using Hyperledger’s Fabric, a permissioned blockchain platform, this paper addresses how these two challenges are resolved. We use eXtensible Access Control Markup Language (XACML) with Abbreviated Language for Authorization (ALFA) as its front-end to specify security rules in Attribute Based Access Control (ABAC). These ABAC rules are then implemented in SC. A large subset of ABAC attributes is stored as metadata in the blockchain. We designed JSON Schema to capture selected data constraints and stored these metadata as blockchain assets. Specialized SC are developed to assure the constraints are satisfied before the assets are changed in the blockchain. The approaches are based on using JSON and JSON schema as the cornerstone of the conceptual data model, capturing metadata of different asset types, and storing metadata in the blockchain.