Implemented a class for RSA decode, but the method throws an error. What is the problem?

Question

PHP

Description of the method

сlass Decode
{
  private $message;
  private $key;

  function __construct ($message, $key) {
    $this->message = $message;
    $this->key = openssl_pkey_get_private($key);
  }

  public function getMessage () {
    $details = openssl_pkey_get_details($this->key);
    $chunkSize = ((4 * (($details['bits'] / 8) / 3) + 3)& ~ 3);
    $output = '';
     
    while ($this->message)
    {
      $chunk = substr($this->message, 0, $chunkSize);
      $this->message = substr($this->message, $chunkSize);
      $decrypted = '';
      if (!openssl_private_decrypt($chunk, $decrypted, $this->key))
      {
        // Именно тут выбрасывается ошибка
        die('Failed to decrypt data');
      }
      $output .= $decrypted;
    }
    openssl_free_key($this->key);

    return $output;
  }	
}

Answer 1

Fence the class where one line is enough...

openssl_private_decrypt($encrypted, $decrypted, openssl_get_privatekey(key));