  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.
