RZcash: A Privacy Protection Scheme for the Account-based Blockchain

In recent years, the Ethereum platform has rapidly emerged, but its privacy issue has become the largest obstacle to the implementation of Ethereum projects. Unlike UTXO-based Bitcoin, Ethereum, the account-based blockchain, requires realtime updates of the account balance. Therefore, its corresponding hidden operation has certain difficulties. We propose a privacy protection scheme called RZcash to solve this problem. It implements the hiding of account balances that are updated in real time, and uses rangeproofs to ensure that the amount of each transaction does not exceed the payer's existing balance. For hiding the payee, we improve the related technology of Monero by using the ciphertext equivalent commitment scheme. We also provide the conversion mechanism and trading method between hidden coins and open coins and describe how RZcash can be combined with an existing account-based blockchain system (such as Ethereum). Finally, we implement the core model of RZcash and evaluate its performance. The evaluation results show that the scheme not only guarantees the privacy and security of the blockchain, but also has good performance in practical applications.