FDLedger: Dynamic and Efficient Anonymous Audit for Distributed Ledgers

Abstract

Distributed ledger schemes supporting users privacy protection have been proposed recently to provide users with better anonymity. However, their schemes made compromises in users addition or deletion, calculation efficiency, and storage overhead. How to implement a work that supports users dynamic addition and deletion with low computational and storage overhead in multi-user scenarios remains a challenging problem. This work introduces our scheme, a more efficient and dynamic user-supported auditing private ledger system. Computational overhead in our scheme is far less than the previous schemes. The storage overhead is independent of the number of transactions, thus only a minimal storage space can store large ledger. Specifically, we firstly propose a new authentication data structure, Sparse Prefix Symbol Tree (SPST), which can be used as an accumulator to implement ledger pruning. Secondly, we introduce a new encryption primitive Order-Revealing Encryption (ORE) to complete cipher text comparison, which reduces the computational overhead and storage space caused by zero-knowledge proof in the original schemes. Thirdly, our scheme use ledger pruning technology and a weighted random sampling algorithm to reduce storage overhead. We provide a formal security concept and conduct a security analysis of our program.