Data processing of blockchain smart contracts

Data processing of blockchain smart contracts

Short answer questions

What problems does the Ethereum virtual machine (EVM) have in processing XML data? The Ethereum virtual machine does not support processing operations on XML data by default, and cannot directly parse or generate data in XML format.

How does the existing Ethereum architecture handle unsupported operations, such as BASE64 encoding? Usually, the code logic that implements the operation is directly written into the smart contract, and the Ethereum virtual machine calls the smart contract to execute, rather than directly executing the pre-deployed code logic.

How efficient is the Ethereum virtual machine in executing the code logic in the smart contract compared to directly executing the locally pre-deployed code logic? The Ethereum virtual machine is less efficient in executing the code logic in the smart contract.

How does the present invention solve the problem that the Ethereum virtual machine does not support certain operations? By extending the EVM instruction set and the smart contract compiler instruction set, adding instructions corresponding to new operations, and pre-deploying the code logic of these operations locally in the EVM.

In Examples 2 and 4, how to solve the stack transfer problem caused by the unfixed data length? Use a pre-compiled contract method, such as a BASE64 encoding smart contract and a BASE64 decoding smart contract, use memory transfer method for parameter transfer, and support reading and writing of data of unfixed length.

How does the new transfer model mentioned in Example 13 protect the user's asset privacy? Instead of using the balance in the external account for transfer, a virtual asset system is used, each asset contains an encrypted amount, and the transaction is verified using a homomorphic encryption algorithm, hiding the actual amount.

In the transfer model of Example 13, how to verify that the transfer user has enough assets to transfer? The balance verification problem is transformed into a problem of verifying whether the input and output are balanced, and the homomorphic encryption algorithm is used to verify whether the sum of the transfer assets and the change assets is equal to the sum of the spent assets.

In the transfer model of Example 13, how to prevent malicious users from using negative amounts for theft? Using a zero-knowledge proof method, verify whether the transfer assets and the change assets are within a reasonable range without exposing the actual amount.

In addition to the operations mentioned in the article, what other operations do you think can be extended to the Ethereum virtual machine? Consider adding operations such as data compression/decompression, encryption algorithms, and search algorithms to improve the functionality and efficiency of smart contracts.

What challenges do you think adding more operations to the Ethereum virtual machine may bring? It may increase the complexity of the EVM, affect execution efficiency, and bring potential security risks, and it is necessary to weigh the pros and cons.

Essay Question

Compare and contrast the advantages and disadvantages of implementing the operation logic directly in the smart contract and extending the EVM instruction set in detail.

Discuss the security factors that need to be considered when introducing new operations in the blockchain virtual machine, and propose corresponding solutions.

Design a new precompiled contract to implement a function that you think is valuable for smart contract development, and explain its working principle in detail.

Explain the role of zero-knowledge proof in protecting user privacy, and explain how to apply zero-knowledge proof in the blockchain system in combination with specific application scenarios.

Explore the advantages and limitations of the virtual asset-based transfer model proposed in this invention, and analyze its impact on the future development of blockchain applications.

Glossary

Term Definition Blockchain virtual machine The execution program that each blockchain node relies on when executing transactions, providing an execution environment for transactions. Smart contract compiler compiles smart contracts written in programming languages ​​into machine language programs that can be recognized and executed by blockchain virtual machines. Business initiation transaction users create business data with business intent through blockchain clients and need to be published to the distributed database of the blockchain. BASE64 encoding/decoding An encoding and decoding operation based on 64 printable characters. RSA signature verification An operation that uses the RSA algorithm to sign and verify data. JSON processing is the processing operation of parsing and generating JavaScript Object Notation (JSON) data. XML processing is the processing operation of parsing and generating Extensible Markup Language (XML) data. Transaction hash is the unique identifier of a transaction, which is calculated by hashing the transaction content. Homomorphic encryption algorithm is an operation that allows calculations to be performed on encrypted data without decryption. Zero-knowledge proof is the ability for a prover to prove to a verifier that he knows the solution to a proposition without revealing any additional information.