Integrasi Rupiah dan Blockchain

Backend (NestJS) – API Konversi Rupiah & Crypto

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+Struktur Folder
+
+backend-conversion/
+├── src/
+│   ├── auth/
+│   ├── users/
+│   ├── conversion/    # Modul utama untuk konversi Rupiah ↔ Crypto
+│   ├── blockchain/
+│   ├── config/
+│   ├── main.ts
+│   ├── app.module.ts
+├── package.json
+└── .env
+
+Instalasi Dependensi
+
+npm install @nestjs/common @nestjs/core @nestjs/config axios ethers web3

Backend (NestJS) – API Pembayaran Merchant

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+Struktur Folder:
+
+backend-payment/
+├── src/
+│   ├── auth/
+│   ├── users/
+│   ├── payments/    # Modul utama untuk pembayaran merchant
+│   ├── blockchain/
+│   ├── config/
+│   ├── main.ts
+│   ├── app.module.ts
+├── package.json
+└── .env
+
+Instalasi Dependensi
+
+npm install @nestjs/common @nestjs/core @nestjs/config axios ethers web3

Frontend (React + Next.js) – Checkout Merchant

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+// pages/checkout.js
+import { useState } from "react";
+import { createPayment } from "../sdk/chainesia-sdk";
+
+export default function Checkout() {
+    const [amount, setAmount] = useState("");
+    const [currency, setCurrency] = useState("idr");
+    const [paymentData, setPaymentData] = useState(null);
+
+    const handlePayment = async () => {
+        const response = await createPayment("MERCHANT_123", amount, currency);
+        setPaymentData(response);
+    };
+
+    return (
+        <div>
+            <h1>Checkout Merchant</h1>
+            <input type="number" value={amount} onChange={e => setAmount(e.target.value)} placeholder="Masukkan jumlah" />
+            <button onClick={handlePayment}>Bayar</button>
+            {paymentData && <p>Status: {paymentData.status}</p>}
+        </div>
+    );
+}

Implementasi Enkripsi AES-256

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+// src/utils/encryption.ts
+import * as crypto from 'crypto';
+
+const algorithm = 'aes-256-cbc';
+const key = Buffer.from(process.env.ENCRYPTION_KEY, 'hex');
+const iv = Buffer.from(process.env.ENCRYPTION_IV, 'hex');
+
+export function encryptData(data: string): string {
+    const cipher = crypto.createCipheriv(algorithm, key, iv);
+    let encrypted = cipher.update(data, 'utf-8', 'hex');
+    encrypted += cipher.final('hex');
+    return encrypted;
+}
+
+export function decryptData(encrypted: string): string {
+    const decipher = crypto.createDecipheriv(algorithm, key, iv);
+    let decrypted = decipher.update(encrypted, 'hex', 'utf-8');
+    decrypted += decipher.final('utf-8');
+    return decrypted;
+}

Keamanan – Enkripsi & Proteksi Fraud

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+// src/utils/encryption.ts
+import * as crypto from 'crypto';
+
+const algorithm = 'aes-256-cbc';
+const key = Buffer.from(process.env.ENCRYPTION_KEY, 'hex');
+const iv = Buffer.from(process.env.ENCRYPTION_IV, 'hex');
+
+export function encryptData(data: string): string {
+    const cipher = crypto.createCipheriv(algorithm, key, iv);
+    let encrypted = cipher.update(data, 'utf-8', 'hex');
+    encrypted += cipher.final('hex');
+    return encrypted;
+}
+
+export function decryptData(encrypted: string): string {
+    const decipher = crypto.createDecipheriv(algorithm, key, iv);
+    let decrypted = decipher.update(encrypted, 'hex', 'utf-8');
+    decrypted += decipher.final('utf-8');
+    return decrypted;
+}

Kode Backend

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+// src/conversion/conversion.service.ts
+import { Injectable } from '@nestjs/common';
+import axios from 'axios';
+import { ethers } from 'ethers';
+
+@Injectable()
+export class ConversionService {
+  private provider = new ethers.JsonRpcProvider(process.env.BLOCKCHAIN_RPC);
+  private wallet = new ethers.Wallet(process.env.PRIVATE_KEY, this.provider);
+
+  async getExchangeRate(from: string, to: string): Promise<number> {
+    const response = await axios.get(`https://api.coingecko.com/api/v3/simple/price?ids=${from}&vs_currencies=${to}`);
+    return response.data[from][to];
+  }
+
+  async convertAndSend(from: string, to: string, amount: number, recipient: string) {
+    const rate = await this.getExchangeRate(from, to);
+    const convertedAmount = amount * rate;
+
+    const tx = await this.wallet.sendTransaction({
+      to: recipient,
+      value: ethers.parseEther(convertedAmount.toString()),
+    });
+
+    return tx.wait();
+  }
+}

Kode Backend – API Pembayaran Merchant

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+// src/payments/payments.service.ts
+import { Injectable } from '@nestjs/common';
+import axios from 'axios';
+import { ethers } from 'ethers';
+
+@Injectable()
+export class PaymentsService {
+  private provider = new ethers.JsonRpcProvider(process.env.BLOCKCHAIN_RPC);
+  private wallet = new ethers.Wallet(process.env.PRIVATE_KEY, this.provider);
+
+  async getExchangeRate(from: string, to: string): Promise<number> {
+    const response = await axios.get(`https://api.coingecko.com/api/v3/simple/price?ids=${from}&vs_currencies=${to}`);
+    return response.data[from][to];
+  }
+
+  async createPayment(merchantId: string, amount: number, currency: string) {
+    const rate = await this.getExchangeRate(currency, 'idr');
+    const convertedAmount = amount * rate;
+
+    // Simpan ke database
+    return {
+      merchantId,
+      amount,
+      currency,
+      convertedAmount,
+      status: 'PENDING'
+    };
+  }
+
+  async processPayment(paymentId: string, sender: string) {
+    // Simpan transaksi ke blockchain
+    const tx = await this.wallet.sendTransaction({
+      to: sender,
+      value: ethers.parseEther("0.01"), // Nominal contoh
+    });
+
+    return tx.wait();
+  }
+}

Kode Frontend

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+// pages/convert.js
+import { useState } from "react";
+import axios from "axios";
+
+export default function ConvertPage() {
+    const [from, setFrom] = useState("idr");
+    const [to, setTo] = useState("ethereum");
+    const [amount, setAmount] = useState("");
+    const [convertedAmount, setConvertedAmount] = useState(null);
+
+    const handleConvert = async () => {
+        const response = await axios.post("/api/convert", { from, to, amount });
+        setConvertedAmount(response.data.convertedAmount);
+    };
+
+    return (
+        <div>
+            <h1>Konversi Rupiah ke Crypto</h1>
+            <input type="number" value={amount} onChange={e => setAmount(e.target.value)} placeholder="Masukkan jumlah" />
+            <button onClick={handleConvert}>Konversi</button>
+            {convertedAmount && <p>Hasil: {convertedAmount} {to.toUpperCase()}</p>}
+        </div>
+    );
+}

Proteksi Slippage (Fluktuasi Harga)

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+// src/conversion/conversion.service.ts
+async convertAndSend(from: string, to: string, amount: number, recipient: string) {
+    const rate = await this.getExchangeRate(from, to);
+    const convertedAmount = amount * rate;
+
+    // Proteksi jika harga berubah lebih dari 1%
+    const maxSlippage = 0.01; // 1%
+    const currentRate = await this.getExchangeRate(from, to);
+    if (Math.abs((currentRate - rate) / rate) > maxSlippage) {
+        throw new Error("Harga berubah terlalu cepat, transaksi dibatalkan.");
+    }
+
+    const tx = await this.wallet.sendTransaction({
+        to: recipient,
+        value: ethers.parseEther(convertedAmount.toString()),
+    });
+
+    return tx.wait();
+}