Gauze: enabling communication-friendly block synchronization with cuckoo filter

Block synchronization is an essential component of blockchain systems. Traditionally, blockchain systems tend to send all the transactions from one node to another for synchronization. However, such a method may lead to an extremely high network bandwidth overhead and significant transmission latency. It is crucial to speed up such a block synchronization process and save bandwidth consumption. A feasible solution is to reduce the amount of data transmission in the block synchronization process between any pair of peers. However, existing methods based on the Bloom filter or its variants still suffer from multiple roundtrips of communications and significant synchronization delay. In this paper, we propose a novel protocol named Gauze for fast block synchronization. It utilizes the Cuckoo filter (CF) to discern the transactions in the receiver’s mempool and the block to verify, providing an efficient solution to the problem of set reconciliation in the P2P (Peer-to-Peer Network) network. By up to two rounds of exchanging and querying the CFs, the sending node can acknowledge whether the transactions in a block are contained by the receiver’s mempool or not. Based on this message, the sender only needs to transfer the missed transactions to the receiver, which speeds up the block synchronization and saves precious bandwidth resources. The evaluation results show that Gauze outperforms existing methods in terms of the average processing latency (about 10\times lower than Graphene) and the total synchronization space cost (about 10\times lower than Compact Blocks) in different scenarios.