🛡️ EVM Arithmetic Safety & Logic Encapsulation

A reference implementation exploring arithmetic safety within the EVM, focusing on mixed-type operations (Signed vs. Unsigned), gas-efficient validation patterns, and strict logic encapsulation.

Unlike high-level languages where arithmetic is abstracted, Solidity requires rigorous handling of storage slots and overflow protection. This project serves as a pattern for handling int256 state changes and enforcing "Fail Early" mechanisms.

🏗 Architecture & Patterns

1. Type Safety (Signed vs. Unsigned)

• Mixed State Strategies: The contract explicitly handles int256 for operations that may result in negative balances or values (Subtraction/Division), demonstrating awareness of EVM storage behavior for signed integers vs. standard uint256 usage.
• Underflow/Overflow Protection: Leverages Solidity 0.8.x built-in overflow checks while maintaining explicit logic for business-rule constraints.

2. Gas Optimization

• Custom Errors vs Strings: Replaced standard require(condition, "Message") with custom error DivisionByZero() and error MaxPowerExceeded().
  • Impact: Reduces bytecode size and runtime gas costs during revert operations.
• Fail-Early Modifiers: Implementation of declarative validation (checkMaxPowerNumber) to decouple security checks from core business logic, ensuring transactions revert before executing heavy arithmetic opcodes.

3. Encapsulation & Observability

• Internal Logic Separation: Core logic (e.g., _subtractionLogic) is isolated in internal pure functions, reducing the attack surface of the public API.
• Event Logging: Emission of indexed events (Addition, Subtraction) to allow off-chain indexers (The Graph) to track state changes without querying contract storage.

🛠 Tech Stack

• Language: Solidity ^0.8.24
• Features: Custom Errors, Modifiers, Event Logging
• License: LGPL-3.0-only

📝 Contract Interface

The system exposes a secured API for arithmetic operations:

// Example of secured entry point
function power(uint256 _num1) external checkMaxPowerNumber(_num1) {
    result = result ** _num1;
}

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Reference implementation for secure arithmetic handling on Ethereum.