Accountable Fine-grained Blockchain Rewriting in the Permissionless Setting

Abstract

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.

Efficient and Fine-grained Redactable Blockchain Supporting Accountability and Updating Policies

“…However, once the user obtains the trapdoor, he can redact data many times, and there is no corresponding trapdoor revocation mechanism. Later, Tian et al [13] proposed a fine-grained rewriting scheme in the permissionless blockchain. The scheme mainly uses attribute-based encryption and dynamic proactive secret sharing to control redacting rights, which is improved in public accountability compared with the previous scheme.…”