Gateway Encryption

const crypto = require('crypto');

function encryptForGateway(payload, m2pRsaPublicKey) {
  // Step 1: Generate random AES-256 key and IV
  const aesKey = crypto.randomBytes(32);
  const iv = crypto.randomBytes(16);

  // Step 2: Encrypt payload with AES-256-CBC
  const cipher = crypto.createCipheriv('aes-256-cbc', aesKey, iv);
  let encryptedData = cipher.update(
    JSON.stringify(payload), 'utf8', 'base64'
  );
  encryptedData += cipher.final('base64');

  // Step 3: Encrypt AES key with RSA public key
  const encryptedKey = crypto.publicEncrypt(
    {
      key: m2pRsaPublicKey,
      padding: crypto.constants.RSA_PKCS1_PADDING
    },
    aesKey
  ).toString('base64');

  // Step 4: Return the encrypted bundle
  return {
    encryptedData,
    encryptedKey,
    iv: iv.toString('base64')
  };
}

import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.*;
import java.util.Base64;

public class GatewayEncryption {

    public static Map<String, String> encrypt(
        String payload, PublicKey m2pRsaPublicKey
    ) throws Exception {
        // Step 1: Generate random AES-256 key and IV
        KeyGenerator keyGen = KeyGenerator.getInstance("AES");
        keyGen.init(256);
        SecretKey aesKey = keyGen.generateKey();
        byte[] iv = new byte[16];
        new SecureRandom().nextBytes(iv);

        // Step 2: Encrypt payload with AES-256-CBC
        Cipher aesCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        aesCipher.init(Cipher.ENCRYPT_MODE, aesKey,
            new IvParameterSpec(iv));
        byte[] encryptedData = aesCipher.doFinal(
            payload.getBytes(StandardCharsets.UTF_8));

        // Step 3: Encrypt AES key with RSA public key
        Cipher rsaCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        rsaCipher.init(Cipher.ENCRYPT_MODE, m2pRsaPublicKey);
        byte[] encryptedKey = rsaCipher.doFinal(aesKey.getEncoded());

        // Step 4: Return the encrypted bundle
        return Map.of(
            "encryptedData", Base64.getEncoder()
                .encodeToString(encryptedData),
            "encryptedKey", Base64.getEncoder()
                .encodeToString(encryptedKey),
            "iv", Base64.getEncoder()
                .encodeToString(iv)
        );
    }
}