Confidential Transaction's Design And Optimization Based On Blockchain And Its Efficiency Analysis

Bitcoin has been the most popular and successful cryptocurrency so far.Blockchain is the most impres-sive technology in bitcoin because of its decentralized property.However,all of the transaction information in blockchain is transparent.For most users who care much about data privacy,bitcoin is not a suitable choice for them.Therefore,confidential transaction is very urgent for these users.Confidential transaction is similar to the transaction in bitcoin,except that all the transaction amounts in confidential transaction are hidden by the transaction users.The core technology in confidential transaction is Pedersen commitment,which is a commitment with addition homomorphic property.Users can hide the transaction amount utilizing Pedersen commitment.However,because of the modular arithmetic in confiden-tial transaction,here comes another problem named "overflow" or rangeproof.In order to solve this problem,we use Borromean ring signature to construct a commitment for the amount's range.In this way,only if the amount in the specific range,the commitment will be valid.Then,we optimize the rangeproof and Borromean ring signature algorithms on time complexity and memory space.In this paper,our contributions are as follows:according to the base transform,we choose the optimized base for the transaction amount so they can publish the fewest numbers of commitments and signatures;using pre-computation,reduce the time of public key generation algorithm by 37%and rangeproof algorithm by 5%;reduce the number of Pedersen commitments and the size of Pedersen commitments;we propose a Borromean ring signature variant aiming to construct the confidential transaction for very small transaction amounts,which can reduce the number of signatures while a little privacy of transaction amounts will be sacrificed.