Technology Review of Blockchain Data Privacy Solutions

Abstract: This objective of this report is to review existing enterprise blockchain technologies - EOSIO powered systems, Hyperledger Fabric and Besu, Consensus Quorum, R3 Corda and Ernst and Young's Nightfall - that provide data privacy while leveraging the data integrity benefits of blockchain. By reviewing and comparing how and how well these technologies achieve data privacy, a snapshot is captured of the industry's current best practices and data privacy models. Major enterprise technologies are contrasted in parallel to EOSIO to better understand how EOSIO can evolve to meet the trends seen in enterprise blockchain privacy. The following strategies and trends were generally observed in these technologies: Cryptography: the hashing algorithm was found to be the most used cryptographic primitive in enterprise or changeover privacy solutions. Coordination via on-chain contracts - a common strategy was to use a shared publicly ledger to coordinate data privacy groups and more generally managed identities and access control. Transaction and contract code sharing: there was a variety of different levels of privacy around the business logic (smart contract code) visibility. Some solutions only allowed authorised peers to view code while others made this accessible to everybody that was a member of the shared ledger. Data migrations for data privacy applications: significant challenges exist when using cryptographically stored data in terms of being able to run system upgrades. Multiple blockchain ledgers for data privacy: solutions attempted to create a new private blockchain for every private data relationship which was eventually abandoned in favour of one shared ledger with private data collections/transactions that were anchored to the ledger with a hash in order to improve scaling.