Feature: Implemented Secure Merchant Vault Architecture with On-chain segregation and Encryption

lib/encryption.ts

@@ -0,0 +1,49 @@
+import crypto from 'crypto';
+
+const ENCRYPTION_KEY = process.env.ENCRYPTION_SECRET || 'fallback_secret_do_not_use_in_production_12345'; // Must be 32 chars for aes-256-gcm
+const IV_LENGTH = 16;
+const ALGORITHM = 'aes-256-gcm';
+
+/**
+ * Encrypts a piece of sensitive text (like a private key)
+ */
+export function encrypt(text: string): string {
+    // Ensure key is 32 bytes
+    const key = crypto.createHash('sha256').update(ENCRYPTION_KEY).digest();
+    const iv = crypto.randomBytes(IV_LENGTH);
+    const cipher = crypto.createCipheriv(ALGORITHM, key, iv);
+    
+    let encrypted = cipher.update(text, 'utf8', 'hex');
+    encrypted += cipher.final('hex');
+    
+    const authTag = cipher.getAuthTag().toString('hex');
+    
+    // Format: iv:authTag:encrypted
+    return `${iv.toString('hex')}:${authTag}:${encrypted}`;
+}
+
+/**
+ * Decrypts an encrypted string back to its original form
+ */
+export function decrypt(encryptedText: string): string {
+    try {
+        const parts = encryptedText.split(':');
+        if (parts.length !== 3) throw new Error('Invalid encrypted text format');
+        
+        const iv = Buffer.from(parts[0], 'hex');
+        const authTag = Buffer.from(parts[1], 'hex');
+        const encrypted = parts[2];
+        
+        const key = crypto.createHash('sha256').update(ENCRYPTION_KEY).digest();
+        const decipher = crypto.createDecipheriv(ALGORITHM, key, iv);
+        decipher.setAuthTag(authTag);
+        
+        let decrypted = decipher.update(encrypted, 'hex', 'utf8');
+        decrypted += decipher.final('utf8');
+        
+        return decrypted;
+    } catch (error) {
+        console.error('Decryption failed:', error);
+        throw new Error('Critical: Could not decrypt sensitive data. Check ENCRYPTION_SECRET.');
+    }
+}

lib/vault-manager.ts

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+import { ethers } from 'ethers';
+import { Keypair } from '@solana/web3.js';
+import bs58 from 'bs58';
+import { db } from './db';
+import { encrypt, decrypt } from './encryption';
+
+/**
+ * Ensures a merchant has EVM and Solana vault wallets.
+ * Generates them if they don't exist.
+ */
+export async function ensureMerchantVaults(merchantId: string) {
+    const result = await db.query(
+        'SELECT id, evm_vault_address, sol_vault_address FROM merchants WHERE id = $1',
+        [merchantId]
+    );
+
+    if (result.rows.length === 0) throw new Error('Merchant not found');
+
+    const merchant = result.rows[0];
+
+    // If already has vaults, skip
+    if (merchant.evm_vault_address && merchant.sol_vault_address) {
+        return {
+            evm: merchant.evm_vault_address,
+            sol: merchant.sol_vault_address
+        };
+    }
+
+    console.log(`[VaultManager] Generating vaults for merchant ${merchantId}...`);
+
+    // 1. Generate EVM Wallet
+    const evmWallet = ethers.Wallet.createRandom();
+    const encryptedEvmKey = encrypt(evmWallet.privateKey);
+
+    // 2. Generate Solana Wallet
+    const solKeypair = Keypair.generate();
+    const encryptedSolKey = encrypt(bs58.encode(solKeypair.secretKey));
+
+    // 3. Save to DB
+    await db.query(
+        `UPDATE merchants SET 
+            evm_vault_address = $1, 
+            evm_vault_key = $2, 
+            sol_vault_address = $3, 
+            sol_vault_key = $4 
+         WHERE id = $5`,
+        [
+            evmWallet.address,
+            encryptedEvmKey,
+            solKeypair.publicKey.toBase58(),
+            encryptedSolKey,
+            merchantId
+        ]
+    );
+
+    return {
+        evm: evmWallet.address,
+        sol: solKeypair.publicKey.toBase58()
+    };
+}
+
+/**
+ * Gets the decrypted private keys for a merchant's vaults.
+ * CRITICAL: Use only when needed (e.g. during manual payout)
+ */
+export async function getMerchantVaultSecrets(merchantId: string) {
+    const result = await db.query(
+        'SELECT evm_vault_key, sol_vault_key FROM merchants WHERE id = $1',
+        [merchantId]
+    );
+
+    if (result.rows.length === 0) throw new Error('Merchant not found');
+
+    const merchant = result.rows[0];
+
+    return {
+        evmKey: merchant.evm_vault_key ? decrypt(merchant.evm_vault_key) : null,
+        solKey: merchant.sol_vault_key ? decrypt(merchant.sol_vault_key) : null
+    };
+}