Smart Contract Security Best Practices

# Smart Contract Security Best Practices

Security is paramount when developing smart contracts. Here are essential practices to follow.

## Key Principles

### 1. Reentrancy Protection
Always use the checks-effects-interactions pattern to prevent reentrancy attacks.

### 2. Access Control
Implement proper access control mechanisms using modifiers.

### 3. Integer Overflow/Underflow
Use SafeMath or Solidity 0.8+ built-in overflow checks.

## Code Example

```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract SecureContract {
mapping(address => uint256) public balances;

function withdraw(uint256 amount) external {
require(balances[msg.sender] >= amount, "Insufficient balance");

balances[msg.sender] -= amount;
(bool success, ) = msg.sender.call{value: amount}("");
require(success, "Transfer failed");
}
}
```

## Testing

Always thoroughly test your contracts with tools like Hardhat and conduct security audits.