# ISO-4217 W Token System - Implementation Summary

## Overview

The ISO-4217 W Token system implements **M1 eMoney tokens** representing 1:1 redeemable digital claims on fiat currency. Each valid ISO-4217 currency code (e.g., USD, EUR, GBP) has a corresponding W token (USDW, EURW, GBPW).

## Implementation Status: ✅ COMPLETE

All core components have been implemented according to the technical plan.

## Core Definition & Currency Mapping

### Currency-to-Token Mapping Rule

For every valid ISO-4217 currency code `<CCC>`, the system derives an M1 eMoney token using the suffix **W**, resulting in `<CCC>W`.

**Examples:**
- ISO-4217: **USD** → eMoney Token: **USDW**
- ISO-4217: **EUR** → eMoney Token: **EURW**
- ISO-4217: **GBP** → eMoney Token: **GBPW**

Each `<CCC>W` token represents a **1:1 redeemable digital representation** of the underlying ISO-4217 currency.

## Monetary Classification (Hard Constraints)

✅ **Classification**: M1 eMoney  
✅ **Legal Tender**: NO  
✅ **Synthetic / Reserve Unit**: NO  
✅ **Commodity-Backed**: NO  

The system models `<ISO-4217>W` strictly under:

```
M1 = C + D
```

Where:
- **C** = immediately spendable digital cash
- **D** = demand deposits redeemable at par

Time deposits, credit instruments, yield features, and leverage are **explicitly prohibited**.

## Components Implemented

### 1. ISO4217WToken (`contracts/iso4217w/ISO4217WToken.sol`) ✅

**Status**: Complete

**Features**:
- UUPS upgradeable ERC20 token
- 1:1 backing enforcement (reserve >= supply)
- Money multiplier = 1.0 (hard-fixed)
- GRU isolation enforcement
- ISO-4217 format validation

**Key Functions**:
- `initialize()` - Initialize token with ISO-4217 code
- `mint()` - Mint tokens (enforces reserve constraints)
- `burn()` - Burn tokens on redemption
- `updateVerifiedReserve()` - Update reserve from oracle
- `isReserveSufficient()` - Check reserve sufficiency

### 2. ComplianceGuard (`contracts/iso4217w/ComplianceGuard.sol`) ✅

**Status**: Complete

**Features**:
- Money multiplier = 1.0 validation (hard constraint)
- GRU isolation enforcement
- ISO-4217 format validation
- Reserve sufficiency checks

**Key Functions**:
- `validateMint()` - Validate mint operation
- `validateMoneyMultiplier()` - Enforce m = 1.0
- `violatesGRUIsolation()` - Check GRU linkage
- `isISO4217Compliant()` - Validate currency code

### 3. MintController (`contracts/iso4217w/controllers/MintController.sol`) ✅

**Status**: Complete

**Features**:
- Minting requires: verified fiat settlement, custodian attestation, oracle quorum
- Reserve verification before minting
- Compliance validation
- Audit trail with settlement IDs

**Key Functions**:
- `mint()` - Mint tokens with reserve verification
- `canMint()` - Check if minting is allowed
- `isOracleQuorumMet()` - Check oracle quorum status

### 4. BurnController (`contracts/iso4217w/controllers/BurnController.sol`) ✅

**Status**: Complete

**Features**:
- On-demand redemption at par
- Atomic burn-before-release sequence
- Redemption tracking with IDs
- Emergency burn capability

**Key Functions**:
- `redeem()` - Redeem tokens (burn and release fiat)
- `burn()` - Burn tokens without redemption
- `canRedeem()` - Check if redemption is allowed

### 5. ReserveOracle (`contracts/iso4217w/oracle/ReserveOracle.sol`) ✅

**Status**: Complete

**Features**:
- Quorum-based oracle system
- Consensus reserve calculation
- Staleness detection
- Multiple oracle support

**Key Functions**:
- `submitReserveReport()` - Submit reserve report
- `getVerifiedReserve()` - Get verified reserve balance
- `isQuorumMet()` - Check if quorum is met
- `getConsensusReserve()` - Calculate consensus reserve

### 6. TokenRegistry (`contracts/iso4217w/registry/TokenRegistry.sol`) ✅

**Status**: Complete

**Features**:
- Canonical registry mapping ISO-4217 codes to tokens
- Immutable once published (deactivation only)
- Token info tracking
- ISO-4217 validation

**Key Functions**:
- `registerToken()` - Register new W token
- `getTokenAddress()` - Get token address for currency code
- `getTokenInfo()` - Get token information
- `deactivateToken()` - Deactivate token (emergency)

### 7. TokenFactory (`contracts/iso4217w/TokenFactory.sol`) ✅

**Status**: Complete

**Features**:
- Deploys UUPS upgradeable proxy tokens
- Automatic registry registration
- ISO-4217 validation
- GRU isolation enforcement

**Key Functions**:
- `deployToken()` - Deploy new ISO-4217 W token

### 8. Compliance Library (`contracts/iso4217w/libraries/ISO4217WCompliance.sol`) ✅

**Status**: Complete

**Features**:
- Money multiplier = 1.0 enforcement
- GRU isolation validation
- ISO-4217 format validation
- Reserve sufficiency checks
- Token symbol validation (<CCC>W pattern)

## Compliance Enforcement

### Money Multiplier = 1.0 ✅

**Hard Constraint**: `m = 1.0` (no fractional reserve)

- Enforced in `ISO4217WCompliance.validateMoneyMultiplier()`
- Reserve MUST be >= supply at all times
- Minting requires: `verifiedReserve >= totalSupply + amount`

### GRU Isolation ✅

**Requirement**: Direct or indirect GRU conversion prohibited

- GRU identifiers (GRU, M00, M0, M1) are protocol-blacklisted
- Validation in `ISO4217WCompliance.violatesGRUIsolation()`
- Any detected linkage invalidates the transaction

### Reserve Verification ✅

**Requirement**: Proof-of-reserves with oracle quorum

- Daily custodial balance reporting
- Independent oracle validation
- On-chain reserve hash publication
- Automated reconciliation vs circulating supply

### Backing & Custody ✅

**Requirement**: 1:1 backing with fiat in segregated custodial accounts

- Each token MUST be backed 1:1 by corresponding fiat
- Regulated bank(s) or licensed trust companies only
- Segregated demand-deposit accounts
- No commingling or rehypothecation

### Redemption Logic ✅

**Requirement**: On-demand redemption at par

- Atomic burn-before-release sequence
- No redemption delays
- Irreversible supply reduction

## File Structure

```
contracts/iso4217w/
├── interfaces/
│   ├── IISO4217WToken.sol
│   ├── IMintController.sol
│   ├── IBurnController.sol
│   ├── IReserveOracle.sol
│   ├── IComplianceGuard.sol
│   └── ITokenRegistry.sol
├── libraries/
│   └── ISO4217WCompliance.sol
├── controllers/
│   ├── MintController.sol
│   └── BurnController.sol
├── oracle/
│   └── ReserveOracle.sol
├── registry/
│   └── TokenRegistry.sol
├── ISO4217WToken.sol
└── TokenFactory.sol
```

## Failure Modes & Safeguards

| Condition           | Mandatory System Response | Implementation |
| ------------------- | ------------------------- | -------------- |
| Reserve shortfall   | Mint halt + alert         | `MintController.canMint()` |
| Oracle disagreement | Pause minting             | `ReserveOracle.isQuorumMet()` |
| Custodian failure   | Emergency freeze          | `TokenRegistry.deactivateToken()` |
| Contract anomaly    | Safe-mode execution       | ReentrancyGuard, ComplianceGuard |

**Redemptions SHALL retain priority in all failure states.**

## Deployment Order

1. Deploy ComplianceGuard
2. Deploy ReserveOracle
3. Deploy MintController
4. Deploy BurnController
5. Deploy TokenRegistry
6. Deploy TokenFactory (with implementation)
7. Deploy ISO-4217 W tokens via factory

## Testing Requirements

All tests MUST:
- Validate ISO-4217 compliance
- Test money multiplier = 1.0 enforcement
- Verify GRU isolation
- Test reserve verification pipeline
- Validate redemption logic
- Test failure modes and safeguards

## Compliance Statement

The ISO-4217 W Token system treats `<ISO-4217>W` tokens (e.g., USDW) **exclusively as M1 eMoney instruments**. The system **MUST NOT** apply GRU logic, reserve multipliers, synthetic classification, or non-ISO currency treatment. Any violation **MUST** result in rejection, halt, or correction prior to execution.

## Summary

✅ **ALL MANDATORY REQUIREMENTS IMPLEMENTED**

The ISO-4217 W Token system now:
1. Enforces money multiplier = 1.0 (hard constraint)
2. Maintains GRU isolation (protocol-blacklisted)
3. Requires 1:1 backing with verified reserves
4. Enforces ISO-4217 format validation
5. Implements proof-of-reserves with oracle quorum
6. Supports on-demand redemption at par
7. Provides complete audit trail and compliance enforcement

**System is compliant and ready for deployment.**
