explorer-monorepo/docs/WETH9_1_TO_1_RATIO_VERIFICATION.md

# WETH9 1:1 Ratio Verification

## Overview

WETH9 (Wrapped Ether) must maintain a strict **1:1 ratio** with ETH. This means:
- **1 ETH = 1 WETH9** (exactly)
- **No fees** should be deducted during wrapping
- **No slippage** should occur
- The contract balance should always equal the total supply

## The Issue

If you're experiencing a ratio that is NOT 1:1, this could indicate:

1. **Contract Implementation Issue**: The WETH9 contract may have been modified
2. **Fee Deduction**: Fees may be incorrectly deducted during deposit
3. **Display/Calculation Error**: The issue may be in how amounts are displayed or calculated
4. **Gas Cost Confusion**: Gas fees are separate from the wrap amount

## Standard WETH9 Implementation

The standard WETH9 `deposit()` function should be:

```solidity
function deposit() public payable {
    balanceOf[msg.sender] += msg.value;
    totalSupply += msg.value;
    Deposit(msg.sender, msg.value);
}
```

**Key Points:**
- `msg.value` is added directly to `balanceOf[msg.sender]` (1:1)
- `msg.value` is added directly to `totalSupply` (1:1)
- No fees are deducted
- No calculations or conversions are performed

## Verification Process

### Step 1: Test the Ratio

Use the verification script to test the actual ratio:

```bash
./scripts/verify-weth9-ratio.sh [private_key] [test_amount]
```

**Example:**
```bash
./scripts/verify-weth9-ratio.sh 0xYourPrivateKey 0.001
```

This script will:
1. Check initial ETH and WETH9 balances
2. Wrap a test amount (e.g., 0.001 ETH)
3. Verify the exact amount of WETH9 received
4. Calculate the ratio
5. Report if the ratio is exactly 1:1

### Step 2: Manual Verification

You can also verify manually:

```bash
# 1. Get initial balances
DEPLOYER=$(cast wallet address --private-key "0xYourPrivateKey")
INITIAL_ETH=$(cast balance "$DEPLOYER" --rpc-url "http://192.168.11.250:8545")
INITIAL_WETH9=$(cast call "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2" \
  "balanceOf(address)" "$DEPLOYER" \
  --rpc-url "http://192.168.11.250:8545")

# 2. Wrap a test amount (0.001 ETH)
TEST_AMOUNT_WEI=$(cast --to-wei 0.001 ether)
cast send "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2" "deposit()" \
  --value "$TEST_AMOUNT_WEI" \
  --rpc-url "http://192.168.11.250:8545" \
  --private-key "0xYourPrivateKey" \
  --gas-price 5000000000

# 3. Wait for confirmation
sleep 15

# 4. Get final balances
FINAL_ETH=$(cast balance "$DEPLOYER" --rpc-url "http://192.168.11.250:8545")
FINAL_WETH9=$(cast call "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2" \
  "balanceOf(address)" "$DEPLOYER" \
  --rpc-url "http://192.168.11.250:8545")

# 5. Calculate differences
ETH_SPENT=$(echo "$INITIAL_ETH - $FINAL_ETH" | bc)
WETH9_RECEIVED=$(echo "$FINAL_WETH9 - $INITIAL_WETH9" | bc)

# 6. Verify ratio
echo "ETH Spent: $ETH_SPENT wei"
echo "WETH9 Received: $WETH9_RECEIVED wei"
echo "Expected: $TEST_AMOUNT_WEI wei"

# They should be equal (WETH9_RECEIVED == TEST_AMOUNT_WEI)
# ETH_SPENT will be higher due to gas fees
```

### Step 3: Check Contract State

Verify the contract maintains proper backing:

```bash
# Check contract ETH balance
CONTRACT_ETH=$(cast balance "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2" \
  --rpc-url "http://192.168.11.250:8545")

# Check total supply
TOTAL_SUPPLY=$(cast call "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2" \
  "totalSupply()" \
  --rpc-url "http://192.168.11.250:8545")

# They should be equal
echo "Contract ETH: $CONTRACT_ETH wei"
echo "Total Supply: $TOTAL_SUPPLY wei"
```

## Common Issues and Solutions

### Issue 1: Gas Fees Confusion

**Problem**: Users think gas fees are part of the wrap ratio.

**Reality**: 
- Gas fees are separate from the wrap amount
- If you wrap 1 ETH, you receive exactly 1 WETH9
- But your ETH balance decreases by 1 ETH + gas fees

**Example:**
```
Initial: 10 ETH
Wrap: 1 ETH
Gas: 0.001 ETH
Result:
  - ETH Balance: 8.999 ETH (10 - 1 - 0.001)
  - WETH9 Balance: 1 WETH9 ✅
  - Ratio: 1:1 ✅ (gas is separate)
```

### Issue 2: Display/Precision Issues

**Problem**: Display rounding makes it appear non-1:1.

**Solution**: Always check raw wei values, not displayed amounts.

```bash
# Use wei for exact comparison
cast call "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2" \
  "balanceOf(address)" "$DEPLOYER" \
  --rpc-url "http://192.168.11.250:8545"
# Returns: 1000000000000000 (0.001 ETH in wei)
```

### Issue 3: Contract Modification

**Problem**: The WETH9 contract may have been modified to include fees.

**Solution**: Inspect the contract bytecode or source code:

```bash
# Get contract bytecode
cast code "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2" \
  --rpc-url "http://192.168.11.250:8545" > weth9_bytecode.bin

# Compare with standard WETH9 bytecode
# Or decompile and check the deposit() function
```

### Issue 4: Incorrect Amount Calculation

**Problem**: Scripts may be calculating amounts incorrectly.

**Solution**: Verify amount calculations in scripts:

```bash
# Always use cast --to-wei for conversion
AMOUNT_WEI=$(cast --to-wei 1.0 ether)
# Result: 1000000000000000000 (exactly 1 ETH in wei)

# Verify before sending
echo "Sending: $AMOUNT_WEI wei"
cast --to-unit "$AMOUNT_WEI" ether
# Should output: 1.0
```

## Expected Behavior

### Correct 1:1 Ratio

```
Input: 1.0 ETH
Output: 1.0 WETH9
Ratio: 1.0 ✅

Input: 0.001 ETH
Output: 0.001 WETH9
Ratio: 1.0 ✅

Input: 100 ETH
Output: 100 WETH9
Ratio: 1.0 ✅
```

### What to Check

1. **WETH9 Received = ETH Deposited** (excluding gas)
2. **Contract Balance = Total Supply** (always)
3. **No fees deducted** from the wrap amount
4. **Exact wei match** (no rounding errors)

## Troubleshooting

### If Ratio is NOT 1:1

1. **Run Verification Script**
   ```bash
   ./scripts/verify-weth9-ratio.sh [private_key] 0.001
   ```

2. **Check Contract Implementation**
   - Inspect the contract bytecode
   - Verify the `deposit()` function logic
   - Check for any fee mechanisms

3. **Review Transaction Details**
   ```bash
   cast tx [transaction_hash] --rpc-url "http://192.168.11.250:8545"
   ```
   - Check the actual value sent
   - Verify the transaction succeeded
   - Check for any events emitted

4. **Compare with Standard WETH9**
   - Standard WETH9 address on Ethereum: `0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2`
   - Verify the implementation matches

### If Verification Fails

1. **Document the Issue**
   - Record the exact amounts (in wei)
   - Note the transaction hash
   - Capture the ratio calculated

2. **Check Contract Source**
   - Request contract source code if available
   - Compare with standard WETH9 implementation
   - Look for modifications

3. **Report the Issue**
   - This is a critical bug if the ratio is not 1:1
   - WETH9 must maintain 1:1 parity for proper functionality

## Script Updates

The wrap script (`wrap-and-bridge-to-ethereum.sh`) has been reviewed and should maintain 1:1 ratio:

- Uses `cast --to-wei` for exact conversion
- Sends exact amount via `--value` flag
- No additional calculations or fees
- Verifies balance after wrapping

If you find the ratio is not 1:1, please:
1. Run the verification script
2. Document the exact amounts
3. Check the contract implementation
4. Report the issue

## Summary

- **WETH9 MUST maintain 1:1 ratio with ETH**
- **No fees should be deducted during wrapping**
- **Gas fees are separate and do not affect the ratio**
- **Always verify using wei values, not displayed amounts**
- **Use the verification script to test the actual ratio**