A Secure and Distributed Construction Document Management System Using Blockchain

Construction Document Management Systems (CDMS) track, manage, and store a variety of documents such as 3D model files, schedules, specifications, and images that are large in size and have different ownerships. The primary objectives of CDMSs are to facilitate document approval workflows, document version management, and security properties such as integrity of data, audit-trail, and approvals. A popular approach for CDMS is to consolidate all the project documents into an on premise or cloud-based centralized location that is owned and managed by a project participant or a trusted third party. Such centralized approaches for electronic documents pose risks such as single points of failures causing loss or corruption of documents and deliberate blocking of access during disputes between the owner of CDMS and other project participants. This situation is particularly challenging in construction projects where project participants cannot fully trust each other due to its inherently fragmented project organizational structure. Therefore, in this paper, a distributed construction document management system using Blockchain and distributed content-addressable storage technologies is presented. Blockchain is a peer-to-peer technology that facilitates distributed computation and irreversible data recording through smart contract and blockchain ledger technologies respectively. Immutability of records and computational logic is facilitated through the unique cryptographic data structure of blockchain ledgers and probabilistic consensus algorithms. In this paper, smart contracts are deployed to facilitate document approval workflows to support processes such as design review and request for information in construction projects. A blockchain ledger data model for tracking workflows and document version management is proposed. Public-key cryptography is deployed to facilitate data confidentiality and integrity in endorsements. A cryptographic indexing structure to support blockchain ledger in document versioning and to validate the authenticity of document search results for CDMS is proposed. The proposed framework also deploys peer-to-peer content-addressable storage for preventing single points of failure and data integrity of documents through data partitioning, data replication, and cryptography. The proposed CDMS is a distributed yet unified platform for managing construction documents. A demonstration of the proposed CDMS is presented with a case-based scenario on request for information (RFI) management.