# AI-Driven Optimization of Blockchain Scalability, Security, and Privacy Protection
## 2 Introduction to Related Technologies
### Blockchain
#### 2.1.3 Smart Contract  
Smart contracts are essentially programs stored on a blockchain that automatically execute specific actions when predefined conditions are met. Typically, smart contracts are used to automate the execution of agreements, allowing all participants to quickly verify transaction outcomes without the need for intermediaries. This enhances efficiency and eliminates unnecessary delays. Additionally, smart contracts can streamline business processes by automatically triggering subsequent actions once certain conditions are fulfilled [49]. Smart contracts operate on an \"if/when...then...\" logic, with conditions encoded on the blockchain. Once triggered and verified, the network automatically executes actions such as fund transfers or asset registration, with outcomes immutably recorded and accessible only to authorized parties [50]. Contract terms are defined by specifying transaction rules, encoding logic conditions, handling exceptions, and establishing dispute resolution mechanisms to ensure reliability and protect participants' interests [51]. The smart contract execution process involves a series of automated steps designed to leverage the inherent technical features of blockchain. As Algorithm 4 shows, initially, the contract is deployed onto the blockchain, with its code and initial state stored immutably in the distributed ledger. Upon receiving an input event, the contract autonomously checks if predefined conditions are satisfied. If so, the corresponding function is executed; otherwise, the input is ignored. During execution, the contract validates input data and blockchain state to ensure correctness. Successful validation results in the state update and event emission, while failure leads to transaction rejection. The immutability of the deployed contract guarantees that neither its code nor its rules can be altered post-deployment, ensuring transparency and trustworthiness. Additionally, contract execution and enforcement are decentralized, with all blockchain nodes independently verifying and applying the contract logic, thus eliminating single points of failure and promoting a trustless operational environment. ```
1:Initialization:
2: Deploy contract C onto the blockchain. 3: Store contract code and initial state in distributed ledger. 4:procedureTriggerEvent(\(input\_event\))
5:if predefined condition \(Cond\) is satisfied then
6: Execute corresponding contract function \(f(Cond)\)
7:else
8: Ignore input; no execution occurs. 9:endif
10:endprocedure
11:procedureContractExecution(\(f(Cond)\))
12: Validate input data and current blockchain state. 13:if Validation succeeds then
14: Update the state variables according to \(f\)'s logic. 15: Emit events or update outputs transparently. 16:else
17: Reject transaction. 18:endif
19:endprocedure
20:procedureImmutability and Verification
21: Once deployed, C cannot be modified. 22: Every transaction involving C is cryptographically verifiable. 23:endprocedure
24:procedureDecentralizedEnforcement
25: All blockchain nodes independently validate and enforce contract execution. 26: No single point of failure or centralized control exists. 27:endprocedure
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**Algorithm 4** Smart Contract Execution Process  
As shown in Table 6, a smart contract is an automated protocol based on blockchain technology that executes predefined operations immediately when specified conditions are met, without the need for human intervention. As shown in Figure 4 below, its core advantages are primarily reflected in the following four aspects: (1) Execution Efficiency and Accuracy: Smart contracts leverage digitalization and automation to significantly reduce human involvement, minimize errors, prevent transaction delays, and enhance overall operational efficiency. (2) Trust and Transparency: The execution records of smart contracts are stored on the blockchain, allowing all participants to access the same data. This ensures transparency, reduces the risk of manipulation or data tampering, and enhances system credibility.