Authenticated Multi-Version Index for Blockchain-based Range Queries on Historical Data

With the rapid growth in emerging applications driven by blockchains, there is an increasing need to support efficient ad hoc querying of authenticated historical data to enable rigorous security and regulatory requirements. The existing blockchain systems offer little or no support for query capabilities over historical data. Although, a full blockchain archive node can be used to maintain historical data of all executed transactions' off the chain, this is not scalable due to data volume. Moreover, such ‘offline’ historical data lack tamper evidence support. To address the above issues, we introduce an authenticated index structure called Authenticated Multi-Version Skip List (AMVSL), designed to support a rich set of query features over historical blockchain data. We further present three range queries: SVRK, MVRK and MVAK, which offer querying over a range of keys and a range of versions. Our experimental evaluation demonstrates that AMVSL can efficiently support these queries and can achieve better performance over existing authenticated data structures.