Criptografía

Toda la comunicación entre AnnA y el cliente se realiza con cifrado 3DES-CBC (Cipher Block Chaining) con un tamaño de bloque de 64 y un tamaño de clave de 192 bytes.

A continuación, algunos ejemplos de implementación para encriptación y desencriptación:

C#/.NET Framework

  public static string Encrypt3DES(string data, string key, string iv)
  {
      byte[] bytes = Encoding.UTF8.GetBytes(data);
      byte[] decodedKey = Convert.FromBase64String(key);
      byte[] decodedIv = Convert.FromBase64String(iv);

      var cryptoServiceProvider = new TripleDESCryptoServiceProvider()
      {
          Key = decodedKey,
          IV = decodedIv,
          Mode = CipherMode.CBC,
          Padding = PaddingMode.PKCS7
      };

      byte[] encrypted = cryptoServiceProvider.CreateEncryptor().TransformFinalBlock(bytes, 0, bytes.Length);
      cryptoServiceProvider.Clear();

      return Convert.ToBase64String(encrypted);
  }

  public static string Decrypt3DES(string data, string key, string iv)
  {
      byte[] encryptedBytes = Convert.FromBase64String(data);
      byte[] decodedKey = Convert.FromBase64String(key);
      byte[] decodedIv = Convert.FromBase64String(iv);

      var cryptoServiceProvider = new TripleDESCryptoServiceProvider()
      {
          Key = decodedKey,
          IV = decodedIv,
          Mode = CipherMode.CBC,
          Padding = PaddingMode.PKCS7
      };

      byte[] bytes = cryptoServiceProvider.CreateDecryptor().TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length);
      cryptoServiceProvider.Clear();

      return Encoding.UTF8.GetString(bytes);
  }

  public static string GenerateIV()
  {
      var cryptoServiceProvider = new TripleDESCryptoServiceProvider();
      cryptoServiceProvider.GenerateIV();

      return Convert.ToBase64String(cryptoServiceProvider.IV);
  }

C#/.NET

  public static string Encrypt3DES(string data, string key, string IV)
  {
      byte[] bytes = Encoding.UTF8.GetBytes(data);
      byte[] convertedKey = Convert.FromBase64String(key);
      byte[] convertedIV = Convert.FromBase64String(IV);

      var cryptoServiceProvider = TripleDES.Create();
      cryptoServiceProvider.Key = convertedKey;
      cryptoServiceProvider.IV = convertedIV;
      cryptoServiceProvider.Mode = CipherMode.CBC;
      cryptoServiceProvider.Padding = PaddingMode.PKCS7;

      byte[] inArray = cryptoServiceProvider.CreateEncryptor().TransformFinalBlock(bytes, 0, bytes.Length);
      cryptoServiceProvider.Clear();

      return Convert.ToBase64String(inArray, 0, inArray.Length);
  }

  public static string Decrypt3DES(string data, string key, string IV)
  {
      byte[] inputBuffer = Convert.FromBase64String(data);
      byte[] convertedKey = Convert.FromBase64String(key);
      byte[] convertedIV = Convert.FromBase64String(IV);

      var cryptoServiceProvider = TripleDES.Create();
      cryptoServiceProvider.Key = convertedKey;
      cryptoServiceProvider.IV = convertedIV;
      cryptoServiceProvider.Mode = CipherMode.CBC;
      cryptoServiceProvider.Padding = PaddingMode.PKCS7;

      byte[] bytes = cryptoServiceProvider.CreateDecryptor().TransformFinalBlock(inputBuffer, 0, inputBuffer.Length);
      cryptoServiceProvider.Clear();

      return Encoding.UTF8.GetString(bytes);
  }

  public static string GenerateIV()
  {
      var auxTdes = TripleDES.Create();
      auxTdes.GenerateIV();
      byte[] IVArray = auxTdes.IV;
      string IV = Convert.ToBase64String(IVArray);

      return IV;
  }

Java

  public String encrypt(String message, SecretKey key, IvParameterSpec iv) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, UnsupportedEncodingException, IllegalBlockSizeException, BadPaddingException {
      final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
      cipher.init(Cipher.ENCRYPT_MODE, key, iv);

      byte[] plainTextBytes = message.getBytes("utf-8");
      byte[] buf = cipher.doFinal(plainTextBytes);
      byte[] base64Bytes = Base64.getEncoder().encode(buf);

      String base64EncryptedString = new String(base64Bytes);

      return base64EncryptedString;
  }

  public String decrypt(String encMessage, SecretKey key, IvParameterSpec iv) throws UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException {
      byte[] message = Base64.getDecoder().decode(encMessage.getBytes("utf-8"));

      final Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
      decipher.init(Cipher.DECRYPT_MODE, key, iv);

      byte[] plainText = decipher.doFinal(message);

      return new String(plainText, "UTF-8");
  }

PHP

  function encrypt3DES($data, $key, $IV)
  {
      $IV  = base64_decode($IV);
      $key = base64_decode($key);
      return openssl_encrypt($data, 'des-ede3-cbc', $key, 0, $IV);
  }

  function decrypt3DES($data, $deckey, $IV)
  {
      $IV = base64_decode($IV);
      $deckey = base64_decode($deckey);
      return openssl_decrypt($data, 'des-ede3-cbc', $deckey, 0, $IV);
  }

Python

  from flask import Flask, request, Response
  from flask_ngrok import run_with_ngrok
  import json
  from Crypto.Cipher import AES, DES3, DES
  from Crypto.Util.Padding import pad, unpad
  from Crypto.Random import get_random_bytes
  from base64 import b64encode, b64decode

  # Initialising a web application with flask
  app = Flask(__name__)

  # For this integration example, NGROK was used to emulate a response server
  run_with_ngrok(app)

  # Encryption method
  def encrypt(data, enckey, iv):
      enckey = b64decode(enckey)
      iv = b64decode(iv)
      cipher = DES3.new(enckey, DES3.MODE_CBC, iv)
      ct_bytes = cipher.encrypt(
          pad(bytes(data, encoding='utf-8'), DES3.block_size))
      ciphertext = b64encode(ct_bytes).decode('utf-8')

      return ciphertext


  # Decryption method
  def decrypt(data, deckey, iv):
      try:
          deckey = b64decode(deckey)
          iv = b64decode(iv)
          data = b64decode(data)
          cipher = DES3.new(deckey, DES3.MODE_CBC, iv)
          pt = unpad(cipher.decrypt(data), DES3.block_size)

          return pt

      except (ValueError, KeyError):
          return 'Incorrect decryption'


  # Get POST AnnA
  @app.route('/get-post', methods=['POST'])
  def receber_post():

      # Encryption Keys
      enckey = 'ENCRYPTION_KEY'
      deckey = 'DECRYPTION_KEY'

      # Retrieving the form sent by AnnA
      data = request.form

      # Recovering the received IV
      ivReceived = data.get('ANNAEXEC')

      # Creating the structure of an AnnA message
      nodeMessage = [
          {
              "PropName": "Alias",
              "PropValue": "msg001"
          },
          {
              "PropName": "Type",
              "PropValue": "MESSAGE"
          },
          {
              "PropName": "Phrase",
              "PropValue": "Hello World!"
          }
      ]

      # Creating the container structure
      container = [
          {
              "PropName": "Container001",
              "PropValue": json.dumps(nodeMessage)
          }
      ]

      # Creating a new IV and encrypting it
      key = get_random_bytes(8)
      cipher = DES.new(key, DES3.MODE_CBC)
      newIV = b64encode(cipher.iv).decode('utf-8')

      # Serialising the container structure and encrypting it
      serialisedContainer = json.dumps(container)
      encryptedSerialisedContainer = encrypt(serialisedContainer, enckey, newIV)

      # Encrypting the new IV
      newIVEncrypted = encrypt(newIV, deckey, ivReceived)

      # Configuring response for AnnA
      replyToAnnA = encryptedSerialisedContainer + ivReceived + newIVEncrypted

      # Replying to AnnA
      response = Response(replyToAnnA, content_type='text/plain')

      # Log
      print('\nData received from AnnA:', data)
      print('\nIV Received:', ivReceived)
      print('\n')
      print('\nNode Message:', nodeMessage)
      print('\nContainer:', container)
      print('\nContainer Serialised:', serialisedContainer)
      print('\nContainer Serialised Encrypted:', encryptedSerialisedContainer)
      print('\n')
      print('\nNew IV:', newIV)
      print('\nNew IV Encrypted:', newIVEncrypted)
      print('\n')
      print('\nReply To AnnA:', replyToAnnA)
      print('\nResponse From AnnA:', response)

      return response

  if __name__ == '__main__':
      app.run()