diff --git a/core/core.services.yml b/core/core.services.yml
index 7cfd0e8..f62ad64 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -126,13 +126,16 @@ services:
     tags:
       - { name: needs_destruction }
     arguments: ['@database']
+  keyvalue.file:
+    class: Drupal\Core\KeyValueStore\KeyValueFileFactory
+    arguments: ['@settings']
   settings:
     class: Drupal\Component\Utility\Settings
     factory_class: Drupal\Component\Utility\Settings
     factory_method: getSingleton
   state:
     class: Drupal\Core\KeyValueStore\State
-    arguments: ['@keyvalue']
+    arguments: ['@keyvalue.file']
     tags:
       - { name: persist }
   queue:
diff --git a/core/lib/Drupal/Core/KeyValueStore/FileStorage.php b/core/lib/Drupal/Core/KeyValueStore/FileStorage.php
new file mode 100644
index 0000000..fd1d37c
--- /dev/null
+++ b/core/lib/Drupal/Core/KeyValueStore/FileStorage.php
@@ -0,0 +1,121 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\KeyValueStore\FileStorage.
+ */
+
+namespace Drupal\Core\KeyValueStore;
+
+/**
+ * Defines the default file key/value store implementation.
+ */
+class FileStorage extends StorageBase {
+
+  /**
+   * The filesystem URI/directory to use as base path.
+   *
+   * @var string
+   */
+  protected $path;
+
+  /**
+   * Overrides \Drupal\Core\KeyValueStore\StorageBase::__construct().
+   *
+   * @param string $collection
+   *   The name of the collection holding key and value pairs.
+   * @param string $path
+   *   The filesystem URI/directory to use as base path.
+   */
+  public function __construct($collection, $path) {
+    parent::__construct($collection);
+    $this->path = $path;
+    if ($this->collection !== '') {
+      // @todo What if $path is a stream wrapper base URI scheme?
+      $this->path .= '/' . $this->collection;
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getMultiple(array $keys) {
+    $values = array();
+    foreach ($keys as $key) {
+      // @todo Inject serialization/encoding format into key/value stores.
+      if (file_exists($this->path . "/$key")) {
+        // @todo DatabaseStorage, being the default implementation, introduced a
+        //   questionable implicit assumption/expectation that it is possible
+        //   to store entire objects (possibly contained in nested arrays even)
+        //   in a key/value store by using serialize() instead of e.g.,
+        //   json_encode($value, TRUE). That aspect of the default implemenation
+        //   pretty much prevents any other implementation to use a better
+        //   serialization format.
+        $values[$key] = unserialize(file_get_contents($this->path . "/$key"));
+      }
+    }
+    return $values;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getAll() {
+    $values = array();
+    foreach ($this->getIterator() as $key => $pathname) {
+      $values[$key] = unserialize(file_get_contents($pathname));
+    }
+    return $values;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function set($key, $value) {
+    file_put_contents($this->path . "/$key", serialize($value));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setIfNotExists($key, $value) {
+    if (!file_exists($this->path . "/$key")) {
+      $this->set($key, $value);
+      return TRUE;
+    }
+    return FALSE;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteMultiple(array $keys) {
+    foreach ($keys as $key) {
+      if (file_exists($this->path . "/$key")) {
+        unlink($this->path . "/$key");
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteAll() {
+    foreach ($this->getIterator() as $key => $pathname) {
+      unlink($pathname);
+    }
+  }
+
+  /**
+   * Returns an iterator for the file storage.
+   *
+   * @return \FilesystemIterator
+   *   The filesystem iterator.
+   */
+  protected function getIterator() {
+    $flags = \FilesystemIterator::KEY_AS_FILENAME | \FilesystemIterator::CURRENT_AS_PATHNAME;
+    $flags |= \FilesystemIterator::SKIP_DOTS;
+    return new \FilesystemIterator($this->path, $flags);
+  }
+
+}
diff --git a/core/lib/Drupal/Core/KeyValueStore/KeyValueFileFactory.php b/core/lib/Drupal/Core/KeyValueStore/KeyValueFileFactory.php
new file mode 100644
index 0000000..4ed3e8f
--- /dev/null
+++ b/core/lib/Drupal/Core/KeyValueStore/KeyValueFileFactory.php
@@ -0,0 +1,42 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\KeyValueStore\KeyValueFileFactory.
+ */
+
+namespace Drupal\Core\KeyValueStore;
+
+use Drupal\Component\Utility\Settings;
+
+/**
+ * Defines the key/value store factory for the file backend.
+ */
+class KeyValueFileFactory implements KeyValueFactoryInterface {
+
+  protected $settings;
+
+  /**
+   * Constructs this factory object.
+   */
+  function __construct(Settings $settings) {
+    $this->settings = $settings;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function get($collection) {
+    // @todo Please disregard this automatic setup. Testing purposes only.
+    $path = $this->settings->get('file_public_path', conf_path() . '/files');
+    $path .= '/keyvalue';
+    if (!is_dir($path)) {
+      mkdir($path, 0777);
+    }
+    if (!is_dir("$path/$collection")) {
+      mkdir("$path/$collection", 0777);
+    }
+    return new FileStorage($collection, $path);
+  }
+
+}