Privacy computing is mainly used to protect the invisible privacy of the original data sent out by the blockchain in complex business scenarios. At present, privacy Computing mainly includes four technical solutions: trusted execution environment (TEE), homomorphic encryption (he), secure multi-party computing (MPC) and zero knowledge proof (zkp).
The combination of privacy computing and blockchain can not only provide data privacy protection, but also solve the performance bottleneck of blockchain. It has become the key research direction of blockchain commercial application. In the future, privacy computing will become a general information infrastructure like blockchain.
Design of private account in Trias
Trias’s privacy account is designed in two modes: account oriented and utxo. It takes the account system as the core to realize the needs of complex services, and utxo supports higher privacy and potential scalability requirements.
At present, many mainstream blockchain project accounts emphasize that their transactions are very safe when they are used, but in fact, the specific operation and use of each account can be seen by chain participants all over the world, which brings certain hidden dangers to chain transactions.
When Trias achieves its goal, it can not only experience the benefits of centralizing anonymous applications on the blockchain, but also protect users’ privacy to the greatest extent and prevent people unrelated to this transaction from being aware of the trend of their assets.
1. Compatible with two accounts
Here is a brief introduction to the differences between account and utxo models.
Account models are easy to understand. Our daily use of bank cards, Alipay, WeChat wallets and other payment methods are based on account model design. Each person’s account has a balance as the status, that is, the current balance is recorded somewhere. This design is called account model. For example, our bank card balance is recorded in the bank’s database.
Utxo model is the basic unit of value transfer created by bitcoin. Its core design idea is stateless, that is, only transaction change events are recorded, not the final state of the transaction. The blockchain system only processes transactions, while the clearing balance and other processes are handled by the node itself.
Overall, the two mechanisms have their own advantages and disadvantages. At present, bitcoin uses utxo and Ethereum uses account.
Utxo: simple principle, easy to expand, highly parallel and strong concealment.
Account: easy to understand, space saving, easy to implement and mature mode.
It involves various operations related to the account, such as account registration, management secret key, permission change, etc. each account has three sets of secret keys. One set supports the operation of account oriented mechanism, one is used for utxo mechanism, one is used to indicate the ownership of the account, and in extreme cases, it can be used for Account Retrieval (cold backup).
2. Transaction privacy support
Trias supports transfer transactions by utxo, and anonymous transfer by hidden address and zero knowledge proof.
Let’s start with the hidden address. Under the working mode of utxo, if account a transfers to account B. Account a will generate a temporary address through the public key of account B and transfer the assets to the corresponding temporary address. In the process of collection, account B needs to go through all effective transactions, and judge whether the payee is itself through the private key and transaction random number.
The process is as follows: account a transfers money to account B. account B has two pairs of public-private key pairs of elliptic curve algorithm, (m, m), (n, n), which specifies that the public parameter of elliptic curve is g:
Calculate the temporary address P through the above process, transfer a to P and disclose R. Account B calculates the private key in the corresponding hidden collection through R. In this way, the whole process of transfer and collection is realized, and the privacy information of account a is protected.
As a hot technology in recent years, zero knowledge proof has been widely discussed and studied by academic circles at home and abroad. What is zero knowledge proof? For example, there is a circular corridor. The exit and entrance are in the same position, and the middle is separated by a locked door. B claims that he has a key. How can a know that B really has a key without getting the key. At this time, a only needs to see B enter from the entrance and exit from the exit, so that a can believe that B holds the key to the door.
Zero knowledge proof means that one party states to the other that a thing is correct without disclosing any information other than the statement. The certifier doesn’t tell you the answer directly, but uses another expression to let you prove it to you until you think the other person really knows the answer. In Trias, zero knowledge proof is mainly realized by zksnark algorithm.
Responsible editor; zl