EVM Compatibility

Orbinum provides full EVM compatibility through Frontier, enabling Ethereum dApps and tooling to work seamlessly.

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Table of Contents

• Overview
• Architecture
• Supported Features
• Gas and Fees
• Precompiles
• Developer Integration

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Overview

Frontier is a set of Substrate pallets that implement:

• EVM execution - Full Ethereum Virtual Machine
• Ethereum RPC - Web3-compatible JSON-RPC
• Transaction format - Ethereum transaction types
• Account model - Unified Substrate/Ethereum accounts

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Architecture

Pallets

Pallet	Purpose
pallet-evm	EVM execution environment
pallet-ethereum	Ethereum transaction handling
pallet-base-fee	EIP-1559 base fee calculation
pallet-dynamic-fee	Dynamic fee adjustment
pallet-evm-chain-id	Chain ID configuration

Account Mapping

Substrate and Ethereum accounts are unified:

Ethereum Address (20 bytes) <-> Substrate AccountId (32 bytes)

Mapping strategy:

// Ethereum address from Substrate account
fn to_ethereum_address(account: AccountId32) -> H160 {
    H160::from_slice(&account.as_ref()[0..20])
}

// Substrate account from Ethereum address
fn to_substrate_account(address: H160) -> AccountId32 {
    let mut data = [0u8; 32];
    data[0..20].copy_from_slice(address.as_bytes());
    AccountId32::from(data)
}

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Supported Features

EIPs Implemented

EIP	Name	Status
EIP-155	Replay protection	Implemented
EIP-1559	Fee market	Implemented
EIP-2930	Access lists	Implemented
EIP-2718	Typed transactions	Implemented
EIP-3855	PUSH0 opcode	Implemented

Transaction Types

Type	EIP	Support
Legacy	Pre-EIP-2718	Yes
EIP-2930	Access list	Yes
EIP-1559	Dynamic fee	Yes

Opcodes

Full EVM opcode support including:

• All arithmetic operations
• Memory/storage operations
• Control flow
• Environmental information
• Block information
• Logging (LOG0-LOG4)
• System operations (CREATE, CALL, etc.)

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Gas and Fees

EIP-1559 Implementation

Base Fee Adjustment

// From pallet-base-fee
fn next_base_fee(
    current: U256,
    gas_used: U256,
    gas_target: U256,
) -> U256 {
    if gas_used > gas_target {
        // Increase base fee
        current + (current * (gas_used - gas_target)) / gas_target / 8
    } else {
        // Decrease base fee
        current - (current * (gas_target - gas_used)) / gas_target / 8
    }
}

Fee Parameters

Parameter	Value	Description
Gas limit	15M	Per-block gas limit
Gas target	7.5M	Target utilization
Min base fee	1 Gwei	Minimum base fee
Max fee change	12.5%	Per-block change limit

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Precompiles

Standard Precompiles

Address	Name	Gas
0x01	ecRecover	3000
0x02	SHA256	60 + 12/word
0x03	RIPEMD160	600 + 120/word
0x04	Identity	15 + 3/word
0x05	Modexp	Variable
0x06	BN254 Add	150
0x07	BN254 Mul	6000
0x08	BN254 Pairing	34000 + 45000/pair
0x09	Blake2	Variable

Custom Precompiles

Orbinum extends precompiles for privacy features:

Address	Name	Purpose
0x800	Poseidon	Poseidon hash
0x801	ShieldedPool	Privacy operations
0x802	ZKVerifier	Proof verification

WIP

Custom precompiles are under development. Interface may change.

Using ZK Precompile

interface IZKVerifier {
    function verifyProof(
        bytes calldata proof,
        bytes32[] calldata publicInputs
    ) external view returns (bool);
}

contract PrivateVault {
    IZKVerifier constant verifier = IZKVerifier(0x802);
    
    function withdraw(
        bytes calldata proof,
        bytes32[] calldata inputs
    ) external {
        require(verifier.verifyProof(proof, inputs), "Invalid proof");
        // Process withdrawal
    }
}

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Developer Integration

Network Configuration

// MetaMask / ethers.js configuration
const network = {
    chainId: '0x1234', // Orbinum chain ID
    chainName: 'Orbinum Testnet',
    nativeCurrency: {
        name: 'ORB',
        symbol: 'ORB',
        decimals: 18
    },
    rpcUrls: ['https://rpc.orbinum.network'],
    blockExplorerUrls: ['https://explorer.orbinum.network']
};

Hardhat Configuration

// hardhat.config.js
module.exports = {
    networks: {
        orbinum: {
            url: 'https://rpc.orbinum.network',
            chainId: 0x1234,
            accounts: [process.env.PRIVATE_KEY],
            gas: 15000000,
            gasPrice: 'auto'
        }
    },
    solidity: {
        version: '0.8.20',
        settings: {
            optimizer: {
                enabled: true,
                runs: 200
            }
        }
    }
};

Deployment Example

const { ethers } = require('hardhat');

async function main() {
    const Token = await ethers.getContractFactory('MyToken');
    const token = await Token.deploy('My Token', 'MTK');
    await token.waitForDeployment();
    
    console.log('Token deployed to:', await token.getAddress());
}

main().catch(console.error);

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Limitations

Limitation	Description	Workaround
Block time	~6s vs Ethereum ~12s	Account for in dApps
Gas metering	Substrate weight-based	Use gas estimates
State size	Trie differences	Optimize storage

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Related Documentation

• System Overview - Full architecture
• Shielded Pool - Privacy integration