基于区块链的可审计隐私保护机密交易

Most current blockchain systems can hardly concurrently satisfy requirements of privacy protection and transaction data auditing. Bitcoin adopts the method of unspent transaction output (UTXO) to ensure that users can quickly query the source as well as fund destinations of each transaction, in order to avoid double spending threats. However, the users’ behaviors, deemed to be privacy, maybe traced by adversaries, since transactions with addresses are stored in the ledger publicly. Even though encryption-based solutions are widely adopted, it often causes restrictions to transaction verifications and auditing. In this paper, we propose an auditable privacy-preserving confidential transaction scheme, which uses Pederson commitment to realize the public verifiability of the transaction rationality without disclosing the specific amount of the transaction. Our scheme supports the initiator of the transaction to initiate the transaction independently without permissions from the receiver, which saves the communication cost comparing with other confidential transaction schemes. By introducing the trapdoor mechanism, the identity of the transaction initiator cannot be recognized by other users outside the ledger and the supervisor, so as to protect users’ privacy. It has realized a variety of audit functions, and different audit methods have been developed according to regulators and private auditors. This paper presents a new range proof method, which has advantages over Prcash when applied to large numbers. The generation time of range proof for 512 bit large numbers is shortened 29.78%, and the generation time of range proof for 1 024 bit large numbers is reduced 56.86%.