One of the fundamental problems that hinders the current blockchain systems for industrial use is scalability. Lightning Network has been proposed to address this challenge, which executes massive amount of transactions off-chain via pre-constructed payment channels, and only records the final state when a payment channel is closed. However, current Lightning Network heavily rely on the single path payment. When the payment value exceeds the deposit of each individual path, the customer has to close all the existing payment channels and construct a new one from scratch, which we term as the overload issue. In addition, the single path payment bears the inherent risk of sensitive information (e.g., payment value) leaking.

Bitcoin blockchain faces the bitcoin scalability problem, for which bitcoin's blocks contain the transactions on the bitcoin network. The on-chain transaction processing capacity of the bitcoin network is limited by the average block creation time of 10 minutes and the block size limit. These jointly constrain the network's throughput. The transaction processing capacity maximum is estimated between 3.3 and 7 transactions per second (TPS). A Layer2 Network, named Lightning Network, is proposed and activated solutions to address this problem. LN operates on top of the bitcoin network as a cache to allow payments to be affected that are not immediately put on the blockchain. However, it also brings some drawbacks. In this paper, we observe a specific payment issue among current LN, which requires additional claims to blockchain and is time-consuming. We call the issue as shares issue. Therefore, we propose Rapido to explicitly address the shares issue. Furthermore, a new smart contract, D-HTLC, is equipped with Rapido as the payment protocol. We finally provide a proof of concept implementation and simulation for both Rapido and LN, in which Rapdio not only mitigates the shares issue but also mitigates the skewness issue thus is proved to be more applicable for various transactions than LN.