const fs = require('fs');
const RSA = require('node-rsa');

const RSA_PUBLIC_KEY = fs.readFileSync('./rsa_public_key.txt', 'utf8');

/**
 * 公钥加密
 *
 * @param {string} plaintext 明文
 * @return {string} 密文
 */
function public_key_encrypt(plaintext) {
  const rsa = new RSA({ b: 1024 });
  rsa.setOptions({ encryptionScheme: 'pkcs1' });
  rsa.importKey(RSA_PUBLIC_KEY, 'public');
  const encrypted = rsa.encrypt(plaintext, 'base64');
  return Buffer.from(encrypted).toString('base64');
}

/**
 * 公钥解密
 *
 * @param {string} ciphertext 密文
 * @return {string} 明文
 */
function public_key_decrypt(ciphertext) {
  const rsa = new RSA({ b: 1024 });
  rsa.importKey(RSA_PUBLIC_KEY, 'public');
  const res = Buffer.from(ciphertext, 'base64').toString('ascii');
  return rsa.decryptPublic(res, 'utf8');
}

// 交易数据
const transaction_data = JSON.stringify({
  amount: 99.99,
  backURL: 'http://dev.meemee.online:8080',
  currency: 'MMK',
  fee: 0.0,
  goods: 'bus',
  merchant: 'oway',
  merchantShortCode: '8810002',
  partnerRefNo: '5920992575054531'
});
const public_key_encrypted = public_key_encrypt(transaction_data);
console.log('public key encrypted: ', public_key_encrypted);

// 交易结果
const encrypted_string = 'SkZzWUg0cTJQVkhnUURLMG84UWFrd3hYc2MyMHBOY3RYZlJNb3ZmMkR3dno5THU2VmJvaEhDN1Nkck14ZlZhd3NyN3JTOHY0M3JHVQ0KQVRlbVVHZWtRMVBwTUxlKzhEempiT1BldlJoRVpvMCsrcUJWcFJaWnNuUUd1aVJWZTllMXNSTi9tait1S2R3eHhMZ3U4Z3MzNk1tcA0KNFAwT3c1WDdDTXc5OVhSTGJOWjN3QncyZC9iTXNxTVM5Sjh1RDZOdmJmeHNlN0dkUUI2YWdRWGkyNEpmRytlVzEvNzZrQkdyKzhPVA0Kd1dTUG1FVER0YVZva3IrcE50KzEzZjVISUtGZTJKVDhMZW1RZTNmOE1kYkVGeHVhRGw2SE96WXlNeGRBR2NyMWNQREQ3ZWg4NkQ1Vw0KSDRtQVRMTDczQ1puTVhhMnpnbDd2YnUxWGpqdU1udkNRR3BIWUE9PQ==';
const decrypted = public_key_decrypt(encrypted_string);
console.log('public key decrypted: ', decrypted);