/**
* Encrypts data using AES-256-CBC encryption.
*
* @param string $secretKey The secret key (32 bytes).
* @param string $vectorKey The initialization vector (16 bytes).
* @param string $data The data to encrypt.
*
* @return string The encrypted data.
* @throws Exception If the key lengths are invalid.
*/
public encryption(secretKey, vectorKey, data)
{
  /* load crypto library */
  const crypto = require('crypto');

  /* Ensure the keys are in the correct format */
  const secretKeyBuffer = Buffer.from(secretKey, 'utf-8');
  const vectorKeyBuffer = Buffer.from(vectorKey, 'hex');

  /* Ensure the secret key is 32 bytes and vector key is 16 bytes */
  if (secretKeyBuffer.length !== 32) throw new Error("Invalid secret key length. Must be 32 bytes!");
  if (vectorKeyBuffer.length !== 16) throw new Error("Invalid initialization vector length. Must be 16 bytes!");

  /* Create encryption cipher */
  const cipher = crypto.createCipheriv('aes-256-cbc', secretKeyBuffer, vectorKeyBuffer);

  /* Encrypt the data */
  var encryptedData = cipher.update(data, 'utf8', 'hex');
  encryptedData += cipher.final('hex');

  /* Return the encrypted data */
  return encryptedData;
}

/**
* Method: encryption
*
* @param   string  $secretKey
* @param   string  $vectorKey
* @param   array   $data
*
* @return  string   $encryptedData
* @throws  Exception
*/
function encryption($secretKey, $vectorKey, $data)
{
  # Convert response data to a string -> optional, based on data you pass to it
  $plaintext = json_encode($data);

  # Ensure the keys are in the correct format
  $secretKey = mb_convert_encoding($secretKey, 'UTF-8');
  $vectorKey = hex2bin($vectorKey);

  # Ensure the secret key is 32 bytes and vector key is 16 bytes
  if (strlen($secretKey) !== 32) throw new Exception("Invalid secret key length. Must be 32 bytes!");
  if (strlen($vectorKey) !== 16) throw new Exception("Invalid initialization vector length. Must be 16 bytes!");

  # Define encryption cipher
  $cipher = 'aes-256-cbc';

  # Let's encrypt the data
  $encryptedData = openssl_encrypt($plaintext, $cipher, $secretKey, OPENSSL_RAW_DATA, $vectorKey);

  # Return the encrypted response
  return bin2hex($encryptedData);
}

/**
* Decrypts data using AES-256-CBC decryption.
*
* @param string $secretKey The secret key (32 bytes).
* @param string $vectorKey The initialization vector (16 bytes).
* @param string $data The data to encrypt.
*
* @return string The decrypted data.
* @throws Exception If the key lengths are invalid.
*/
public decryption(secretKey, vectorKey, data)
{
  /* Ensure the keys are in the correct format /
  const secretKeyBuffer = Buffer.from(secretKey, 'utf-8');
  const vectorKeyBuffer = Buffer.from(vectorKey, 'hex');

  /* Ensure the secret key is 32 bytes and vector key is 16 bytes /
  if (secretKeyBuffer.length !== 32) throw new Error("Invalid secret key length. Must be 32 bytes!");
  if (vectorKeyBuffer.length !== 16) throw new Error("Invalid initialization vector length. Must be 16 bytes!");

  /* create decryption cipher /
  const decipher = crypto.createDecipheriv('aes-256-cbc', secretKeyBuffer, vectorKeyBuffer);

  /* decrypt the requested data /
  let decryptedBody = decipher.update(data, 'hex', 'utf8');
  decryptedBody += decipher.final('utf8');

  /* Return the decrypted response /
  return decryptedBody;
}