protected function _importKey($key, $isFile)
    {
        $result    = array();
        $arguments = array();
        $input     = $this->_prepareInput($key, $isFile, false);
        $version   = $this->engine->getVersion();

        if (version_compare($version, '1.0.5', 'ge')
            && version_compare($version, '1.0.7', 'lt')
        ) {
            $arguments[] = '--allow-secret-key-import';
        }

        if (empty($this->passphrases)) {
            $arguments[] = '--batch';
        }

        $this->engine->reset();
        $this->engine->setPins($this->passphrases);
        $this->engine->setOperation('--import', $arguments);
        $this->engine->setInput($input);
        $this->engine->run();

        return $this->engine->getProcessData('Import');
    }