LDSP: Shopping with Cryptocurrency Privately and Quickly under Leadership

LDSP is a layer-2 cryptocurrency payment system that supports a dynamic and distributed setup with scalability and payer privacy. Different from the statekeeping merchant consortium assumed by a recent layer-2 solution Snappy (NDSS 2020), its core idea is to rely on leaders selected from the merchants to lead a mini-consortium and ensure the fungibility of the LDSP coins. Similar to Snappy, payers can transfer coins off-chain, enjoying low-latency transactions, while the merchants are assured that they will receive the coins. Privacy-wise, Snappy requires all merchants to check the whole customer transaction history, which is not necessary for LDSP.