Private Data Objects (PDO) enables sharing of data and coordinating action amongst mutually distrusting parties. Interaction is mediated through a “smart contract” that defines data access and update policies that are carried with the object regardless of where it resides or how often it changes hands. The smart contracts policies are enforced through execution in a Trusted Execution Environment (TEE).
PDO uses a distributed ledger, in this case the Microsoft Confidential Consortium Framework (CCF) distributed ledger, to ensure that there is a single, authoritative instance of the object, and to provide a means of guaranteeing atomicity of updates across interacting objects. PDO performs contract execution and storage off the blockchain, with only a hash of blockchain state stored on the distributed ledger. Currently, the PDO/CCF combo is restricted to simulated enclaves.
PDO provides benefits for both application developers seeking to define and implement privacy-preserving distributed ledgers, and for service providers seeking to provide blockchain services.
For the application developer, smart contracts implemented with PDO ensure that contract state is completely hidden from all participants, including contract validators, and allows contracts to be stored off-chain. Policies and data are bound up together in the PDO smart contract; polices travel with the data no matter how the smart contract object is shared or with whom. The PDO smart contact provides an enforceable agreement for multi-party data sharing and analytics.
For service providers, PDO provides scalable performance; separation of contract execution from ordering allows the performance of contract execution to scale with available hardware. Because PDO contract execution occurs off the blockchain, redundancy is limited to the applications requirements rather than the entire blockchain, providing fewer potential targets for compromise.
Please see the PDO Contracts open-source repository for sample smart contracts developed using the Private Data Objects framework. Our examples cover smart contracts for managing fungible and non-fungible assets, contracts that can be used to set up a fair exchange of assets among multiple parties, etc. Please use these sample contracts as guide to develop your own PDO smart contracts. We encourage you to share your use-cases including solution approaches to the PDO Contracts repository.
Instructions for installing/building Hyperledger Private Data Objects can be found in the build documentation.
The usage document describes what you can do with a functional PDO installation.
For more information about how Private Data Objects work, see the specification document.
A paper with a more formal overview of Private Data Objects is available HERE.
A presentation about Private Data Objects is available HERE.
Hyperledger Private Data Objects operates as a Hyperledger Labs project. This code is provided solely to demonstrate basic PDO mechanisms and to facilitate collaboration to refine PDO architecture and define minimum viable product requirements. The code provided in this repository is prototype code and not intended for production use.
Dan Middleton (dan.middleton@intel.com)
Hyperledger Private Data Objects software is released under the Apache License Version 2.0 software license. See the license file for more details.
Hyperledger Private Data Objects documentation is licensed under the Creative Commons Attribution 4.0 International License. You may obtain a copy of the license at: http://creativecommons.org/licenses/by/4.0/.