Bank of America Crypto: Enterprise DeFi Compliance Guide for Financial Institutions

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import "@openzeppelin/contracts/access/AccessControl.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

contract EnterpriseDefiVault is AccessControl, Pausable, ReentrancyGuard {
    // Role definitions for compliance hierarchy
    bytes32 public constant COMPLIANCE_OFFICER = keccak256("COMPLIANCE_OFFICER");
    bytes32 public constant RISK_MANAGER = keccak256("RISK_MANAGER");
    bytes32 public constant AUDITOR = keccak256("AUDITOR");
    
    // Transaction monitoring for BSA compliance
    struct Transaction {
        address from;
        address to;
        uint256 amount;
        uint256 timestamp;
        bytes32 transactionHash;
        bool flagged; // AML flag for suspicious activity
    }
    
    mapping(bytes32 => Transaction) public transactions;
    mapping(address => bool) public kycVerified;
    mapping(address => uint256) public dailyTransactionVolume;
    
    // Daily transaction limits for AML compliance
    uint256 public constant MAX_DAILY_VOLUME = 10000 * 10**18; // $10,000 equivalent
    
    modifier onlyKycVerified(address account) {
        require(kycVerified[account], "KYC verification required");
        _;
    }
    
    modifier withinDailyLimits(address account, uint256 amount) {
        require(
            dailyTransactionVolume[account] + amount <= MAX_DAILY_VOLUME,
            "Daily transaction limit exceeded"
        );
        _;
    }
    
    constructor() {
        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
        _grantRole(COMPLIANCE_OFFICER, msg.sender);
    }
    
    // Compliant deposit function with full audit trail
    function deposit(uint256 amount, bytes32 source) 
        external 
        onlyKycVerified(msg.sender)
        withinDailyLimits(msg.sender, amount)
        nonReentrant
        whenNotPaused
    {
        // Record transaction for BSA reporting
        bytes32 txHash = keccak256(abi.encodePacked(
            msg.sender, 
            amount, 
            block.timestamp,
            source
        ));
        
        transactions[txHash] = Transaction({
            from: msg.sender,
            to: address(this),
            amount: amount,
            timestamp: block.timestamp,
            transactionHash: txHash,
            flagged: false
        });
        
        // Update daily volume tracking
        dailyTransactionVolume[msg.sender] += amount;
        
        // Emit event for off-chain monitoring systems
        emit TransactionRecorded(txHash, msg.sender, amount, source);
        
        // Execute deposit logic
        _processDeposit(msg.sender, amount);
    }
    
    // Compliance officer can flag suspicious transactions
    function flagTransaction(bytes32 txHash) 
        external 
        onlyRole(COMPLIANCE_OFFICER) 
    {
        transactions[txHash].flagged = true;
        emit TransactionFlagged(txHash, msg.sender);
    }
    
    // Emergency pause for regulatory compliance
    function emergencyPause() external onlyRole(COMPLIANCE_OFFICER) {
        _pause();
        emit EmergencyPauseActivated(msg.sender, block.timestamp);
    }
    
    event TransactionRecorded(bytes32 indexed txHash, address indexed user, uint256 amount, bytes32 source);
    event TransactionFlagged(bytes32 indexed txHash, address indexed officer);
    event EmergencyPauseActivated(address indexed officer, uint256 timestamp);
}

// Real-time AML monitoring service
class ComplianceMonitor {
    constructor(web3Provider, contractAddress) {
        this.web3 = new Web3(web3Provider);
        this.contract = new this.web3.eth.Contract(contractABI, contractAddress);
        this.suspiciousPatterns = new Set();
        this.watchlist = new Map(); // OFAC sanctioned addresses
    }
    
    async monitorTransactions() {
        // Listen for transaction events
        this.contract.events.TransactionRecorded({
            fromBlock: 'latest'
        })
        .on('data', async (event) => {
            const transaction = await this.analyzeTransaction(event);
            
            if (this.isSuspicious(transaction)) {
                await this.flagTransaction(transaction.txHash);
                await this.notifyComplianceOfficers(transaction);
            }
            
            // Generate BSA reports for transactions over $3,000
            if (transaction.amount > this.web3.utils.toWei('3000', 'ether')) {
                await this.generateCTR(transaction); // Currency Transaction Report
            }
        });
    }
    
    isSuspicious(transaction) {
        // Check against OFAC sanctions list
        if (this.watchlist.has(transaction.from) || this.watchlist.has(transaction.to)) {
            return true;
        }
        
        // Detect structuring patterns (amounts just under reporting thresholds)
        const amount = parseFloat(this.web3.utils.fromWei(transaction.amount, 'ether'));
        if (amount > 2900 && amount < 3000) {
            return true;
        }
        
        // Flag high-frequency small transactions
        const recentTxCount = this.getRecentTransactionCount(transaction.from, 3600); // 1 hour
        if (recentTxCount > 10 && amount < 1000) {
            return true;
        }
        
        return false;
    }
    
    async generateCTR(transaction) {
        // Generate Currency Transaction Report for FinCEN
        const report = {
            reportType: 'CTR',
            transactionDate: new Date(transaction.timestamp * 1000),
            amount: this.web3.utils.fromWei(transaction.amount, 'ether'),
            customerInfo: await this.getCustomerKYC(transaction.from),
            transactionHash: transaction.txHash,
            reportingInstitution: 'Bank of America',
            filingDate: new Date()
        };
        
        // Submit to FinCEN BSA E-Filing system
        await this.submitToFinCEN(report);
    }
}

# Example pilot program configuration
pilot_parameters:
  duration: 120_days
  max_participants: 100
  transaction_limits:
    daily: $1000
    monthly: $5000
  supported_assets:
    - USD_stablecoin
    - treasury_token
  monitoring_level: enhanced
  reporting_frequency: daily

# Python implementation for real-time compliance checking
import asyncio
from web3 import Web3
from dataclasses import dataclass
from typing import List, Dict
import logging

@dataclass
class ComplianceAlert:
    transaction_hash: str
    alert_type: str
    risk_score: int
    timestamp: int
    customer_id: str
    amount: float

class EnterpriseComplianceEngine:
    def __init__(self, web3_provider: str, contract_address: str):
        self.w3 = Web3(Web3.HTTPProvider(web3_provider))
        self.contract_address = contract_address
        self.ofac_list = self.load_ofac_sanctions()
        self.transaction_patterns = {}
        
    async def process_transaction(self, tx_hash: str) -> List[ComplianceAlert]:
        """
        Analyze transaction for compliance violations
        Returns list of alerts for compliance review
        """
        alerts = []
        tx_receipt = self.w3.eth.get_transaction_receipt(tx_hash)
        
        # Check OFAC sanctions list
        if await self.check_sanctions(tx_receipt.to, tx_receipt.from):
            alerts.append(ComplianceAlert(
                transaction_hash=tx_hash,
                alert_type="OFAC_VIOLATION",
                risk_score=10,  # Highest risk
                timestamp=tx_receipt.timestamp,
                customer_id=tx_receipt.from,
                amount=self.w3.from_wei(tx_receipt.value, 'ether')
            ))
        
        # Detect structuring patterns
        structuring_risk = await self.analyze_structuring(tx_receipt)
        if structuring_risk > 7:
            alerts.append(ComplianceAlert(
                transaction_hash=tx_hash,
                alert_type="STRUCTURING_PATTERN",
                risk_score=structuring_risk,
                timestamp=tx_receipt.timestamp,
                customer_id=tx_receipt.from,
                amount=self.w3.from_wei(tx_receipt.value, 'ether')
            ))
        
        # Generate SAR if multiple high-risk indicators present
        if len([a for a in alerts if a.risk_score >= 8]) >= 2:
            await self.generate_sar(tx_receipt, alerts)
        
        return alerts
    
    async def generate_sar(self, transaction, alerts):
        """Generate Suspicious Activity Report for FinCEN filing"""
        sar_data = {
            'report_type': 'SAR-DI',  # Suspicious Activity Report - Digital Currency
            'filing_institution': 'Bank of America',
            'transaction_date': transaction.timestamp,
            'suspicious_activity': [alert.alert_type for alert in alerts],
            'customer_info': await self.get_customer_kyc(transaction.from),
            'narrative': self.generate_sar_narrative(alerts),
            'filing_deadline': transaction.timestamp + (30 * 24 * 3600)  # 30 days
        }
        
        # Submit to FinCEN BSA E-Filing System
        await self.submit_sar(sar_data)
        logging.info(f"SAR filed for transaction {transaction.hash}")

// Risk assessment checklist embedded in smart contract
contract RiskAssessment {
    struct ContractRisk {
        uint8 liquidityRisk;      // 1-10 scale
        uint8 counterpartyRisk;   // 1-10 scale  
        uint8 technicalRisk;      // 1-10 scale
        uint8 regulatoryRisk;     // 1-10 scale
        bool auditCompleted;
        bool boardApproved;
        uint256 maxExposure;      // Maximum bank exposure in USD
    }
    
    mapping(address => ContractRisk) public protocolRisks;
    
    modifier onlyApprovedProtocols(address protocol) {
        require(protocolRisks[protocol].boardApproved, "Protocol not approved");
        require(protocolRisks[protocol].auditCompleted, "Audit required");
        _;
    }
    
    function calculateOverallRisk(address protocol) 
        public 
        view 
        returns (uint8) 
    {
        ContractRisk memory risk = protocolRisks[protocol];
        return (risk.liquidityRisk + risk.counterpartyRisk + 
                risk.technicalRisk + risk.regulatoryRisk) / 4;
    }
}

// Integration layer between DeFi and traditional banking
class BankingSystemBridge {
    constructor(coreBankingAPI, defiProvider) {
        this.coreAPI = coreBankingAPI;
        this.defi = defiProvider;
        this.reconciliationSchedule = new Map();
    }
    
    async processCustomerDefiTransaction(customerId, amount, operation) {
        // Verify customer exists in core banking system
        const customer = await this.coreAPI.getCustomer(customerId);
        if (!customer.isActive || customer.riskRating === 'HIGH') {
            throw new Error('Customer not eligible for DeFi services');
        }
        
        // Check available balance in traditional account
        const balance = await this.coreAPI.getAccountBalance(customer.primaryAccountId);
        if (operation === 'DEPOSIT' && balance.available < amount) {
            throw new Error('Insufficient funds in traditional account');
        }
        
        // Execute DeFi transaction
        const defiTx = await this.defi.executeTransaction({
            customer: customerId,
            amount: amount,
            operation: operation,
            sourceAccount: customer.primaryAccountId
        });
        
        // Record transaction in core banking system
        await this.coreAPI.recordTransaction({
            accountId: customer.primaryAccountId,
            amount: operation === 'DEPOSIT' ? -amount : amount,
            description: `DeFi ${operation} - ${defiTx.hash}`,
            transactionCode: 'DEFI_OPERATION',
            externalReference: defiTx.hash
        });
        
        // Schedule daily reconciliation
        this.scheduleReconciliation(customer.primaryAccountId, defiTx.hash);
        
        return defiTx;
    }
    
    async dailyReconciliation() {
        // Reconcile all DeFi positions with core banking records
        const defiBalances = await this.defi.getAllCustomerBalances();
        const bankingBalances = await this.coreAPI.getDefiAccountBalances();
        
        for (const [customerId, defiBalance] of defiBalances) {
            const bankBalance = bankingBalances.get(customerId) || 0;
            const variance = Math.abs(defiBalance - bankBalance);
            
            if (variance > 0.01) { // Variance greater than 1 cent
                await this.createReconciliationException({
                    customerId,
                    defiBalance,
                    bankBalance,
                    variance,
                    date: new Date()
                });
            }
        }
    }
}