DLT Interoperability and More ⛓️#17 — Generic Privacy Preserving Private Permissioned Blockchains⛓️
In this series, we analyze papers on blockchain and interoperability.
This edition covers a paper on a paper that proposes anonymity mechanisms for private blockchains.
➡️ Title: Generic Privacy Preserving Private Permissioned Blockchains
➡️ Authors: Frédéric A Hayek, Mirko Koscina, Pascal Lafourcade, Charles Olivier-Anclin
➡️ Paper source: https://hal.uca.fr/hal-03906880/document
➡️ Background:
To read this paper, basic background on privacy is useful. Quoting from the paper:
“A good example of pseudonymity is Bitcoin [31], where users are identified by their public keys, and it is generally infeasible to trace the public key to a real-world identity. Note that in bitcoin a user can create as many pseudonyms as they wish. Anonymity, on another hand, is when it is infeasible to link anything. One such example is Monero’s usage of ring signatures [36] in order to anonymize the sender’s identity that is blended with a set of other identities”.
➡️ Contributions:
- The authors propose a privacy-enhanced adaptation of Hyperledger Fabric powered by a BFT consensus algorithm.
💪 Strong points:
- Good work on the background on signature schemes, which helps understand the paper in detail. In particular, the authors use blind signatures, group signatures, and ring signatures.
- The PBFT-based algorithm inspired by Fabric is well-described.
- The paper explains in simple terms how can anonymity and pseudonymity be achieved for user transactions and ordered / endorser operations.
🤞 Suggestions for improvement:
- It would be interesting to see a formal analysis of the proposed protocols, e.g., using the UC framework.
🔥 Points of interest:
- Blind signatures and group signatures are used for anonymity. They rely on authority.
- Looks like, structurally, the proposal relies on Hyperledger Fabric with minimal changes.
🚀 What are the implications for our work?
Understanding techniques for privacy and security allow us to design more dependable blockchain interoperability middleware.
