Accountable Fine-grained Blockchain Rewriting in the Permissionless Setting
This addresses the need for secure and accountable transaction modifications in open blockchains, which is an incremental improvement over existing methods lacking accountability.
The paper tackles the problem of enabling fine-grained blockchain rewriting in permissionless settings while ensuring accountability, allowing modifiers' identities and privileges to be traced for malicious changes. It presents a generic framework, an instantiation with evaluation analysis, and demonstrates integration into open blockchains.
Blockchain rewriting with fine-grained access control allows a user to create a transaction associated with a set of attributes, while another user (or modifier) who possesses enough rewriting privileges from a trusted authority satisfying the attribute set can rewrite the transaction. However, it lacks accountability and is not designed for open blockchains that require no trust assumptions. In this work, we introduce accountable fine-grained blockchain rewriting in a permissionless setting. The property of accountability allows the modifier's identity and her rewriting privileges to be held accountable for the modified transactions in case of malicious rewriting (e.g., modify the registered content from good to bad). We first present a generic framework to secure blockchain rewriting in the permissionless setting. Second, we present an instantiation of our approach and show its practicality through evaluation analysis. Last, we demonstrate that our proof-of-concept implementation can be effectively integrated into open blockchains.