EDEN Token Retirement Contract

A secure smart contract that enables users to retire EDEN tokens for ETH at a fixed exchange rate during a specified time window. The contract implements an atomic swap mechanism where users receive ETH immediately upon depositing EDEN tokens.

Features

• Fixed Exchange Rate: Admin-defined exchange rate set at deployment
• Atomic Swaps: Users receive ETH immediately when depositing EDEN
• Time-Bounded Window: Configurable deposit period using block numbers
• Permanent Token Lock: EDEN tokens are permanently locked (effectively burned)
• Admin Controls: Pausable functionality and ETH recovery after deposit window
• Security: ReentrancyGuard protection and comprehensive input validation

Technical Overview

The system consists of:

• EdenTokenRetirement: Core contract managing the EDEN-to-ETH exchanges
• Fixed exchange rate immutably set at deployment
• Immediate ETH distribution upon EDEN deposit

Key Functionalities

• Deposit EDEN tokens and receive ETH instantly at fixed rate
• Gas-efficient permit-based deposits using EIP-2612 (single transaction)
• Admin can deposit ETH to fund exchanges
• Admin can withdraw remaining ETH after deposit window closes
• Pausable functionality for emergency situations
• View functions to check exchange rates and balances

Getting Started

Prerequisites

• Node.js (v14 or higher)
• npm or yarn
• Hardhat

Installation

1. Clone the repository:

git clone https://github.com/eden-network/token-retirement.git
cd token-retirement

2. Install dependencies:

npm install

Testing

Run the test suite:

npm test

For gas reporting:

npm run test:gas

Generate test coverage report:

npm run test:coverage

Deployment

The contract deployment uses environment variables configured in the .env file.

Configuration

1. Set up your .env file with the following variables:

# EDEN token address (required)
EDEN_ADDRESS=0x1559fa1b8f28238fd5d76d9f434ad86fd20d1559

# Exchange rate: EDEN tokens per 1 ETH (default: 57000)
EXCHANGE_RATE=57000

# Start date for deposits (format: YYYY-MM-DD)
START_DATE=2025-07-29

# Optional start time (format: HH:MM or HH:MM:SS, UTC)
# START_TIME=12:00

# End date for EDEN deposits (format: YYYY-MM-DD)
END_DATE=2025-07-31

# Optional end time (format: HH:MM or HH:MM:SS, UTC)
# END_TIME=23:59

# OR use duration in blocks instead of end date (mutually exclusive with END_DATE)
# EDEN_DEPOSIT_DURATION=86400  # ~14 days at 12s/block

# Contract owner address (defaults to deployer if not set)
CONTRACT_OWNER=0xYourOwnerAddress

# Verify contract on Etherscan after deployment
VERIFY=true

# For mainnet deployments, set this to true to confirm
# CONFIRM=true

# Optional gas configuration
# GAS_PRICE=20  # in gwei
# GAS_LIMIT=8000000

Parameters:

• EDEN_ADDRESS: Address of the EDEN token contract (required)
• EXCHANGE_RATE: Number of EDEN tokens per 1 ETH (defaults to 57000 for 1000 EDEN = 0.0175429 ETH)
• CONTRACT_OWNER: Owner address for the contract (defaults to deployer)
• VERIFY: Set to true to verify contract on Etherscan after deployment
• CONFIRM: Set to true to confirm mainnet deployment

Time Window Options:

1. Duration in blocks:

   • Use EDEN_DEPOSIT_DURATION=86400 for ~14 days at 12s/block

2. Date-based (recommended):

   • Use START_DATE and END_DATE in YYYY-MM-DD format
   • Optionally add START_TIME and END_TIME for specific times (UTC)
   • If no time is specified, start defaults to 00:00:00 and end defaults to 23:59:59

Deploy Commands:

Local deployment:

npm run deploy:local

Testnet deployment:

npm run deploy:sepolia

Mainnet deployment:

npm run deploy:mainnet

Example Configurations:

Basic Sepolia deployment (in .env):

EDEN_ADDRESS=0x1559fa1b8f28238fd5d76d9f434ad86fd20d1559
EXCHANGE_RATE=57000
START_DATE=2025-07-29
END_DATE=2025-08-29
CONTRACT_OWNER=0xYourOwnerAddress
VERIFY=true

Duration-based deployment (in .env):

EDEN_ADDRESS=0x1559fa1b8f28238fd5d76d9f434ad86fd20d1559
EXCHANGE_RATE=57000
EDEN_DEPOSIT_DURATION=172800  # ~30 days
CONTRACT_OWNER=0xYourOwnerAddress
VERIFY=true

Precise timing deployment (in .env):

EDEN_ADDRESS=0x1559fa1b8f28238fd5d76d9f434ad86fd20d1559
EXCHANGE_RATE=1000
START_DATE=2024-12-25
START_TIME=12:00:00
END_DATE=2024-12-31
END_TIME=23:59:59
CONTRACT_OWNER=0xYourOwnerAddress
VERIFY=true

Mainnet deployment (in .env):

EDEN_ADDRESS=0x1559fa1b8f28238fd5d76d9f434ad86fd20d1559
EXCHANGE_RATE=57000
START_DATE=2024-12-25
END_DATE=2024-12-31
CONTRACT_OWNER=0xYourOwnerAddress
VERIFY=true
CONFIRM=true  # Required for mainnet

Post-Deployment Steps

1. Fund the contract with ETH:

   • Send ETH to the deployed contract address before the deposit window starts
   • Ensure sufficient ETH for expected EDEN deposits

2. Verify the contract (if on public network):

   npx hardhat verify --network <network> <contract-address> <constructor-args>

3. Monitor deposits:

   • Check totalEdenDeposited() to track EDEN deposits
   • Use getContractETHBalance() to monitor available ETH

Contract Interaction

For Users

1. Check exchange rate:

   uint256 rate = contract.EXCHANGE_RATE();  // EDEN per 1 ETH

2. Calculate ETH received:

   uint256 ethAmount = contract.getETHAmount(edenAmount);

3. Exchange EDEN for ETH (two options):

   Option A: Traditional (2 transactions):

   • First approve the contract to spend EDEN tokens
   • Call depositEdenForETH(amount) during the deposit window
   • Receive ETH immediately

   Option B: With Permit (1 transaction, gas efficient):

   • Sign permit message off-chain
   • Call depositEdenForETHWithPermit(amount, deadline, v, r, s)
   • Approve and swap in single transaction

For Admin

1. Fund contract: Send ETH directly to contract address

2. Pause/Unpause (emergency):

   contract.pause();
   contract.unpause();

3. Withdraw remaining ETH (after deposit window):

   contract.withdrawRemainingETH();

Security Considerations

• EDEN tokens sent to the contract are permanently locked
• Contract uses ReentrancyGuard for withdrawal protection
• Exchange rate is immutable after deployment
• Admin cannot withdraw EDEN tokens
• Permit functionality uses EIP-2612 standard for secure off-chain approvals
• Comprehensive test coverage for edge cases and permit scenarios

Development Commands

Compile contracts:

npm run compile

Run linter:

npm run lint

Fix linting issues:

npm run lint:fix

Format code:

npm run format

Start local node:

npm run node

License

This project is licensed under the MIT License