PPSC: A Privacy-Preserving Stateless Cryptocurrency System

Empowered by the blockchain technology, cryptocurrencies have become quite popular in recent years. In account-based cryptocurrency systems, maintaining the state of every account is essential for a node to validate transactions, which generally requires a large storage space. In addition to this efficiency issue, privacy issues in cryptocurrency systems attract people's increasing attention. To address the above issues, this paper proposes a privacy-preserving stateless cryptocurrency system named PPSC. Specifically, PPSC reduces the storage cost of a node by employing the aggregatable sub-vector commitment scheme (aSVC). The node only needs to maintain a commitment of the large state vector. And transactions can be validated in a stateless manner. The aSVC scheme is also utilized to hide the value of a transaction. By utilizing the ring signature scheme, PPSC can hide the sender and the receiver of a transaction from third parties. Simulation results demonstrate that PPSC is space efficient, and the time overhead for privacy preserving is acceptable.