Redacting Transactions from Execute-Order-Validate Blockchains. (arXiv:2105.14818v2 [cs.CR] UPDATED)

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