Objects.yaml

# Use an own publishing configuration
TYPO3\Flow\Resource\Publishing\ResourcePublishingTargetInterface:
  className: Venodor\Package\Resource\Publishing\SecureFileSystemPublishingTarget

SecureFileSystemPublishingTarget.php

<?php
namespace Vendor\Package\Resource\Publishing;

/*                                                                        *
 * This script belongs to the TYPO3 Flow framework.                       *
 *                                                                        *
 * It is free software; you can redistribute it and/or modify it under    *
 * the terms of the GNU Lesser General Public License, either version 3   *
 * of the License, or (at your option) any later version.                 *
 *                                                                        *
 * The TYPO3 project - inspiring people to share!                         *
 *                                                                        */

use TYPO3\Flow\Annotations as Flow;

/**
 * Publishing target for a file system.
 *
 * @Flow\Scope("singleton")
 */
class SecureFileSystemPublishingTarget extends \TYPO3\Flow\Resource\Publishing\FileSystemPublishingTarget {

	/**
	 * @var \TYPO3\Flow\Session\SessionInterface
	 * @Flow\Inject
	 */
	protected $session;

	/**
	 * Returns the web URI to be used to publish the specified persistent resource
	 *
	 * @param \TYPO3\Flow\Resource\Resource $resource The resource to build the URI for
	 * @return string The web URI
	 */
	protected function buildPersistentResourceWebUri(\TYPO3\Flow\Resource\Resource $resource) {
		$filename = $resource->getFilename();
		// check if the session already contains a secureDownloadToken
		if (!$this->session->hasKey('secureDownloadToken')) {
			// if not, generate one and store it in the session
			$randomToken = \TYPO3\Flow\Utility\Algorithms::generateRandomToken(20);
			$this->session->putData('secureDownloadToken', $randomToken);
		}
		$rewrittenFilename = ($filename === '' || $filename === NULL) ? '' : '/' . $this->rewriteFilenameForUri($filename);
		// add the secure download token to the uri
		return $this->getResourcesBaseUri() . 'Persistent/' .  $this->session->getData('secureDownloadToken') . '/' . $resource->getResourcePointer()->getHash() . $rewrittenFilename;
	}

	/**
	 * Returns the publish path and filename to be used to publish the specified persistent resource
	 *
	 * @param \TYPO3\Flow\Resource\Resource $resource The resource to build the publish path and filename for
	 * @param boolean $returnFilename FALSE if only the directory without the filename should be returned
	 * @return string The publish path and filename
	 */
	protected function buildPersistentResourcePublishPathAndFilename(\TYPO3\Flow\Resource\Resource $resource, $returnFilename) {
		if (!$this->session->hasKey('secureDownloadToken')) {
			$randomToken = \TYPO3\Flow\Utility\Algorithms::generateRandomToken(20);
			$this->session->putData('secureDownloadToken', $randomToken);
		}
		// add the secure download token to the path
		$publishPath = $this->resourcesPublishingPath . 'Persistent/' . $this->session->getData('secureDownloadToken') . '/';
		if (!is_dir($publishPath)) {
			\TYPO3\Flow\Utility\Files::createDirectoryRecursively($publishPath);
		}

		if ($returnFilename === TRUE) return $publishPath . $resource->getResourcePointer()->getHash() . '.' . $resource->getFileExtension();
		return $publishPath;
	}

}

?>

SessionAspect.php

<?php

namespace Vendor\Package\Resource\Publishing;
use TYPO3\Flow\Annotations as Flow;

/**
* @Flow\Aspect
*/
class SessionAspect {

	/**
	* @Flow\Inject
	* @var \TYPO3\Flow\Session\SessionInterface
	*/
	protected $session;

	/**
	* Remove private persistent resources on garbage collection
	*
	* @param \TYPO3\Flow\AOP\JoinPointInterface $joinPoint
	* @Flow\Before("method(TYPO3\Flow\Session\Session->destroy())")
	* @return void
	*/
	public function removePrivatePersistentResources(\TYPO3\Flow\AOP\JoinPointInterface $joinPoint) {
		if ($this->session->hasKey('secureDownloadToken')) {
			// if we have a secure download token in the session...			
			$directory = FLOW_PATH_WEB . '_Resources/Persistent/' . $this->session->getData('secureDownloadToken') . '/';
			if (is_dir($directory)) {
				// ... and we have a folder name like it, delete it on destroying the session
				\TYPO3\Flow\Utility\Files::removeDirectoryRecursively($directory);
			}
		}
	}

}

?>

Settings.yaml

Vendor:
  Package:

    resource:

      publishing:

        # If enabled, the publisher will check if the static resources of active packages
        # have changed and if so publishes them again. If disabled, static package resources
        # are only published once and changes are unnoticed until the related cache is flushed.
        detectPackageResourceChanges: FALSE

        # Options for the File System publishing target
        fileSystem:

          # Strategy for mirroring files: Either "copy" or "link"
          mirrorMode: link