Analysis of Duplicate Packing in FruitChain

Nakamoto's blockchain faces fairness and security barriers. Recently a famous blockchain protocol called FruitChain has been proposed to solve the two problems. In FruitChain, each miner performs hashing operations with a low difficulty to mine a fruit containing transactions. These fruits are then packed into blocks. The low difficulty implies that many miners might mine fruits in a short interval and the broadcasting nature of the blockchain network means that these miners might pack transactions from a similar transaction set into fruits. Therefore, in FruitChain, a transaction might be packed into multiple fruits. This paper is the first to identify the problem of duplicate packing in FruitChain. We then develop a theoretical model taking into account all kinds of factors (e.g., fruit generation rate, fruit size, network delay) to analyze the probability of duplicate packing of a transaction. Extensive simulations verify that our theoretical model is very accurate. This study is helpful for providing guidance for configuring FruitChain parameters.