| Blockchain is a new technology that is emerging with the increasing popularity of digital cryptocurrencies such as Bitcoin.Blockchain has attracted much attention because of its characteristics of decentralized,tamper-proofing,openness and transparency.The importance of blockchain is self-evident,from blockchain 1.0,which is primarily used in digital currency and payment behavior,to blockchain 2.0,which automates a range of operations,to blockchain 3.0,which is used in healthcare,industry,culture,health,art,and more.With the popularity of blockchain,more and more people pay attention to and use blockchain,and blockchain has the characteristics of openness and transparency,easy to cause user privacy leakage.Therefore,blockchain privacy protection has become an important research area.Currently more mainstream cryptocurrencies,such as Bitcoin and Ethereum,simply provide users with a pseudonym.Cryptocurrencies such as Dash,Zcash,and Monero began to use crypto-technology to protect users’ privacy.However,its security is mainly based on discrete number problems,bilinear pairing of Diffie-Hellman problems,large integer decomposition problems and so on.With the advent of the quantum computer era,there are potential security threats in these programs.As a kind of cryptosystem which is expected to resist quantum attack,the lattice cryptography has attracted much attention.The main work of this paper is to explore the blockchain privacy protection in the field of cryptocurrencies,and propose a solution based on the lattice cryptography.The scheme is divided into the following three parts:(1)Combining the characteristics of multi-input and multi-output of Bitcoin,this article adopts and improves the one-time linkable ring signature scheme proposed by Wilson Abel Alberto Torres et al.to hide the real address of the transaction initiator in multiple addresses.At the same time,because of the use of linkable ring signature,it can effectively prevent malicious users "double spending".(2)In this article,we abandon the way that the actual transaction amount is written directly in the blockchain in Bitcoin,but use homomorphic commitments to hide the transaction amount after homomorphic encryption of the amount.(3)In this article merge into the idea of one-time address by Monero.whenever the new transaction is generated,the recipient of the transaction randomly generates the new address,thus protecting the identity information of the recipient of the transaction.This article gives the comparison of the transaction structure of blockchain before and after transformation,and analyzes the correctness and security of the scheme.Through the above scheme,the privacy protection of both parties on the blockchain is effectively realized. |
