First, the privacy protection of transaction information, the privacy protection of the sender, the recipient and the transaction amount of the transaction, including mixed currency, ring signature and confidential transaction.

The second is the privacy protection of smart contracts. The protection scheme for contract data includes zero-knowledge proof, multi-party secure computing, homomorphic encryption and so on.

the third is the privacy protection of data on the chain, mainly including account book isolation, private data and data encryption and authorized access.

1. Blockchain encryption algorithm separates identity information from transaction data

1. Transaction data on the blockchain, including transaction address, amount, transaction time, etc., are open and transparent. However, the identity of the user corresponding to the transaction address is anonymous. Through the blockchain encryption algorithm, the separation of user identity and user transaction data is realized. Before the data is stored in the blockchain, the user's identity information can be hashed, and the obtained hash value can be used as the unique identifier of the user. The chain stores the user's hash value instead of the real identity data information, and the user's transaction data and hash value are bundled instead of the user's identity information.

2. As a result, the data generated by users are true, and when using these data for research and analysis, due to the irreversibility of blockchain, everyone can't restore the private data of registered users' names, phone numbers, email addresses, etc. through hash values, which plays a role in protecting privacy.

Second, blockchain "encrypted storage+distributed storage"

Encrypted storage means that access to data must provide a private key. Compared with ordinary passwords, private keys are more secure and can hardly be cracked by violence. The characteristics of distributed storage and decentralization reduce the risk of all data being leaked to a certain extent, while centralized database storage, once the database is attacked and invaded by hackers, all data is easily stolen. Users' data privacy can be better protected through "encrypted storage+distributed storage".

3. Blockchain * * * knowledge mechanism to prevent individual risks

* * knowledge mechanism is a mechanism for blockchain nodes to reach a network-wide consensus on block information, which can ensure that the latest block is accurately added to the blockchain, and the blockchain information stored by the nodes is consistent, and can resist malicious attacks. One of the values of blockchain lies in the * * * knowledge management of data, that is, all users have equal management rights for the data on the chain, so the risk of individual mistakes is eliminated from the operation first. Through the whole network knowledge of blockchain, data decentralization can be solved, and the problem of verification can be solved by using zero-knowledge proof, so that the scene of using user privacy data in an open decentralized system can be realized, while meeting the needs of the Internet platform, some data is still only in the hands of users.

iv. Zero-knowledge proof of blockchain

Zero-knowledge proof means that the prover can convince the verifier that a certain assertion is correct without providing any useful information to the verifier, that is, the prover can fully prove that he is the legitimate owner of a certain right without leaking relevant information, that is, the "knowledge" to the outside world is "zero". Using zero-knowledge proof technology, we can verify the correlation of data under the condition of ciphertext, and realize the data * * * enjoyment while ensuring data privacy.