PRETRUST: A Framework for Fast Payments in Blockchain System

Decentralized cryptocurrencies based on blockchains hold an advantage over the conventional methods in digital payments. However, many current decentralized cryptocurrencies based on blockchains cannot manage to satisfy the requests for fast payments. In fact, most time cost on blockchains is the time waiting for records to be verified. The efficiency of addressing transactions will be greatly improved if this part of the time can be saved. One motivation is to scale out the capacity by reducing interactions with the public chain while keeping its original structure, which is a mainstream strategy of improving efficiency. In the paper, we propose PRETRUST, a new framework to address the problem above. PRETRUST is based on consortium blockchains thoughts, supporting fast payments. In order to make parties address transactions and scale-out the capacity, the main strategy is based on the guarantee mechanism and shard technology with a random arrangement of transactions and consensus groups. In PRETRUST, the guarantee process replaces the verification of a transaction on-chain. And the model of a trusted execution environment is utilized in the interactions between PRETRUST and public systems. Throughout the paper, we discuss several transaction scenarios and analyze the security, which shows that PRETRUST can guarantee security.