Redacting Transactions from Execute-Order-Validate Blockchains
It addresses privacy concerns for users in blockchain systems, offering a practical solution for compliance without sacrificing consistency, though it is incremental as it builds on existing blockchain frameworks.
The paper tackles the problem of user privacy in execute-order-validate blockchains by designing the first redactable system that allows users to exercise the right to be forgotten, implemented on Hyperledger Fabric with minimal performance overhead.
As user privacy gains popularity and attention, and starts to shape relations between users and service providers, blockchain based solutions thrive for ways to relax immutability without sacrificing consistency. This work answers that need and presents the first design for a redactable execute-order-validate blockchain, that grants users with the \emph{right to be forgotten}. The design is easy to adopt, as we exemplify by implementing it on top of Hyperledger Fabric. It modifies the block structure and extracts user data from the hash-chain without loosening any correctness or liveness criteria. We evaluate our design and show that it provides compliance with only a minimal performance overhead, making it a feasible add-on to any execute-order-validate blockchain system.