diff --git a/core/lib/Drupal/Core/File/File.php b/core/lib/Drupal/Core/File/File.php
index b35f5ee..9a08a7d 100644
--- a/core/lib/Drupal/Core/File/File.php
+++ b/core/lib/Drupal/Core/File/File.php
@@ -22,6 +22,13 @@ class File extends Entity {
   public $fid;
 
   /**
+   * The file UUID.
+   *
+   * @var integer
+   */
+  public $uuid;
+
+  /**
    * The file language code.
    *
    * @var string
diff --git a/core/lib/Drupal/Core/File/FileStorageController.php b/core/lib/Drupal/Core/File/FileStorageController.php
index 940e1fd..0ec948c 100644
--- a/core/lib/Drupal/Core/File/FileStorageController.php
+++ b/core/lib/Drupal/Core/File/FileStorageController.php
@@ -9,6 +9,8 @@ namespace Drupal\Core\File;
 
 use Drupal\entity\DatabaseStorageController;
 use Drupal\entity\EntityInterface;
+use Drupal\Component\Uuid\Uuid;
+
 
 /**
  * File storage controller for files.
@@ -28,7 +30,16 @@ class FileStorageController extends DatabaseStorageController {
     if (!isset($values['filemime']) && isset($values['uri'])) {
       $values['filemime'] = file_get_mimetype($values['uri']);
     }
-    return parent::create($values);
+
+    // Create file object via parent class constructor.
+    $file = parent::create($values);
+
+    // Generate and add UUID.
+    $uuid = new Uuid();
+    $file->uuid = $uuid->generate();
+
+
+    return $file;
   }
 
   /**
diff --git a/core/modules/comment/comment.install b/core/modules/comment/comment.install
index 4b3c9fc..24b1832 100644
--- a/core/modules/comment/comment.install
+++ b/core/modules/comment/comment.install
@@ -91,6 +91,13 @@ function comment_schema() {
         'not null' => TRUE,
         'description' => 'Primary Key: Unique comment ID.',
       ),
+      'uuid' => array(
+        'description' => 'The universally unique identifier for a comment.',
+        'type' => 'varchar',
+        'length' => 36,
+        'not null' => TRUE,
+        'default' => '',
+      ),
       'pid' => array(
         'type' => 'int',
         'not null' => TRUE,
@@ -181,6 +188,7 @@ function comment_schema() {
       'comment_uid' => array('uid'),
       'comment_nid_langcode' => array('nid', 'langcode'),
       'comment_created' => array('created'),
+      'uuid' => array('uuid'),
     ),
     'primary key' => array('cid'),
     'foreign keys' => array(
@@ -282,6 +290,30 @@ function comment_update_8000() {
 }
 
 /**
+ * Create an uuid column for comment table.
+ *
+ * @ToDo: Batch generate uuids for all existing comments without a uuid.
+ */
+function comment_update_8001() {
+  db_add_field(
+    'comment',
+    'uuid',
+    array(
+      'description' => 'The universally unique identifier for a comment.',
+      'type' => 'varchar',
+      'length' => 36,
+      'not null' => TRUE,
+      'default' => '',
+    ),
+    array(
+      'indexes' => array(
+        'uuid' => array('uuid'),
+      )
+    )
+  );
+}
+
+/**
  * @} End of "addtogroup updates-7.x-to-8.x".
  * The next series of updates should start at 9000.
  */
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 7c96247..348f95d 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -109,6 +109,7 @@ function comment_entity_info() {
         'id' => 'cid',
         'bundle' => 'node_type',
         'label' => 'subject',
+        'uuid' => 'uuid',
       ),
       'bundles' => array(),
       'view modes' => array(
diff --git a/core/modules/comment/lib/Drupal/comment/Comment.php b/core/modules/comment/lib/Drupal/comment/Comment.php
index 101a679..1603de7 100644
--- a/core/modules/comment/lib/Drupal/comment/Comment.php
+++ b/core/modules/comment/lib/Drupal/comment/Comment.php
@@ -22,6 +22,13 @@ class Comment extends Entity {
   public $cid;
 
   /**
+   * The comment UUID.
+   *
+   * @var integer
+   */
+  public $uuid;
+
+  /**
    * The parent comment ID if this is a reply to a comment.
    *
    * @var integer
diff --git a/core/modules/comment/lib/Drupal/comment/CommentStorageController.php b/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
index b041ebd..2bfa752 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
@@ -9,6 +9,8 @@ namespace Drupal\comment;
 
 use Drupal\entity\EntityInterface;
 use Drupal\entity\DatabaseStorageController;
+use Drupal\Component\Uuid\Uuid;
+
 
 /**
  * Defines the controller class for comments.
@@ -19,6 +21,19 @@ use Drupal\entity\DatabaseStorageController;
 class CommentStorageController extends DatabaseStorageController {
 
   /**
+   * Overrides Drupal\entity\DatabaseStorageController::create().
+   */
+  public function create(array $values) {
+    $comment = parent::create($values);
+
+    // Generate and add UUID.
+    $uuid = new Uuid();
+    $comment->uuid = $uuid->generate();
+
+    return $comment;
+  }
+
+  /**
    * Overrides Drupal\entity\DatabaseStorageController::buildQuery().
    */
   protected function buildQuery($ids, $conditions = array(), $revision_id = FALSE) {
diff --git a/core/modules/entity/entity.api.php b/core/modules/entity/entity.api.php
index 37263a6..1d9462a 100644
--- a/core/modules/entity/entity.api.php
+++ b/core/modules/entity/entity.api.php
@@ -77,6 +77,9 @@
  *       'subject' should be specified here. If complex logic is required to
  *       build the label, a 'label callback' should be defined instead (see
  *       the 'label callback' section above for details).
+ *     - uuid (optional): The name of the property that contains the universally
+ *       unique identifier of the entity, which is used to distinctly identify
+ *       an entity across different Drupal installations.
  *   - bundle keys: An array describing how the Field API can extract the
  *     information it needs from the bundle objects for this type (e.g
  *     $vocabulary objects for terms; not applicable for nodes). This entry can
@@ -148,6 +151,7 @@ function hook_entity_info() {
         'id' => 'nid',
         'revision' => 'vid',
         'bundle' => 'type',
+        'uuid' => 'uuid',
       ),
       'bundle keys' => array(
         'bundle' => 'type',
diff --git a/core/modules/entity/entity.module b/core/modules/entity/entity.module
index daaa9f6..a339df7 100644
--- a/core/modules/entity/entity.module
+++ b/core/modules/entity/entity.module
@@ -217,6 +217,54 @@ function entity_load($entity_type, $id, $reset = FALSE) {
 }
 
 /**
+ * Load entity from the database by given UUID.
+ *
+ * If an entity type supports a UUID-type entity identifier, this function can
+ * find an entity by that UUID-type entity identifier.
+ * Not all entities support that kind of UUID-type entity identifier
+ * (which can be defined in hook_entity_info).
+ *
+ * @param string $entity_type
+ *   The entity type to load, e.g. node or user.
+ * @param string $uuid
+ *   The uuid of the entity to load.
+ * @param bool $reset
+ *   Whether to reset the internal cache for the requested entity type.
+ *
+ * @return EntityInterface|FALSE
+ *   The entity object, or FALSE if there is no entity with the given UUID.
+ *
+ * @see hook_entity_info()
+ *
+ */
+function entity_load_by_uuid($entity_type, $uuid, $reset = FALSE) {
+  $entity = FALSE;
+
+  // Only consider entities that have a "uuid"-type key declared via
+  // hook_entity_info.
+  $entity_info = entity_get_info($entity_type);
+  if (is_array($entity_info) && isset($entity_info['entity keys']) && isset($entity_info['entity keys']['uuid'])) {
+    $uuid_key_name = $entity_info['entity keys']['uuid'];
+
+    // Retrieve entity record for given uuid to get its entity id.
+    $entity_query = new Drupal\entity\EntityFieldQuery();
+    $entity_query_result = $entity_query->entityCondition('entity_type', $entity_type)
+      ->propertyCondition($uuid_key_name, $uuid)
+      ->range(0, 1)
+      ->execute();
+
+    // Mine result for entity id and load the entity by its id.
+    if (is_array($entity_query_result) && isset($entity_query_result[$entity_type])) {
+      $entity_ids = array_keys($entity_query_result[$entity_type]);
+      $entity_id = array_shift($entity_ids);
+      $entity = entity_load($entity_type, $entity_id, $reset);
+    }
+  }
+
+  return $entity;
+}
+
+/**
  * Loads multiple entities from the database.
  *
  * This function should be used whenever you need to load more than one entity
diff --git a/core/modules/node/lib/Drupal/node/Node.php b/core/modules/node/lib/Drupal/node/Node.php
index 1aac6fb..9694624 100644
--- a/core/modules/node/lib/Drupal/node/Node.php
+++ b/core/modules/node/lib/Drupal/node/Node.php
@@ -29,6 +29,13 @@ class Node extends Entity {
   public $vid;
 
   /**
+   * The node UUID.
+   *
+   * @var integer
+   */
+  public $uuid;
+
+  /**
    * The node content type (bundle).
    *
    * @var string
diff --git a/core/modules/node/lib/Drupal/node/NodeStorageController.php b/core/modules/node/lib/Drupal/node/NodeStorageController.php
index aa52582..b5958fa 100644
--- a/core/modules/node/lib/Drupal/node/NodeStorageController.php
+++ b/core/modules/node/lib/Drupal/node/NodeStorageController.php
@@ -10,6 +10,7 @@ namespace Drupal\node;
 use Drupal\entity\DatabaseStorageController;
 use Drupal\entity\EntityInterface;
 use Drupal\entity\EntityStorageException;
+use Drupal\Component\Uuid\Uuid;
 use Exception;
 
 /**
@@ -31,6 +32,10 @@ class NodeStorageController extends DatabaseStorageController {
       $node->created = REQUEST_TIME;
     }
 
+    // Generate and add UUID.
+    $uuid = new Uuid();
+    $node->uuid = $uuid->generate();
+
     return $node;
   }
 
diff --git a/core/modules/node/node.install b/core/modules/node/node.install
index 6f806e9..34aebd8 100644
--- a/core/modules/node/node.install
+++ b/core/modules/node/node.install
@@ -27,6 +27,13 @@ function node_schema() {
         'not null' => FALSE,
         'default' => NULL,
       ),
+      'uuid' => array(
+        'description' => 'The universally unique identifier for a node.',
+        'type' => 'varchar',
+        'length' => 36,
+        'not null' => TRUE,
+        'default' => '',
+      ),
       'type' => array(
         'description' => 'The {node_type}.type of this node.',
         'type' => 'varchar',
@@ -114,6 +121,7 @@ function node_schema() {
       'uid'                 => array('uid'),
       'tnid'                => array('tnid'),
       'translate'           => array('translate'),
+      'uuid'                => array('uuid'),
     ),
     'unique keys' => array(
       'vid' => array('vid'),
@@ -543,6 +551,31 @@ function node_update_8002() {
 }
 
 /**
+ * Create an uuid column for node table.
+ *
+ * @ToDo: Batch generate uuids for all existing nodes without a uuid.
+ */
+function node_update_8003() {
+  db_add_field(
+    'node',
+    'uuid',
+    array(
+      'description' => 'The universally unique identifier for a node.',
+      'type' => 'varchar',
+      'length' => 36,
+      'not null' => TRUE,
+      'default' => '',
+    ),
+    array(
+      'indexes' => array(
+        'uuid' => array('uuid'),
+      )
+    )
+  );
+}
+
+
+/**
  * @} End of "addtogroup updates-7.x-to-8.x".
  * The next series of updates should start at 9000.
  */
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index e787c7d..8c8a482 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -204,6 +204,7 @@ function node_entity_info() {
         'revision' => 'vid',
         'bundle' => 'type',
         'label' => 'title',
+        'uuid' => 'uuid',
       ),
       'bundle keys' => array(
         'bundle' => 'type',
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index 9ba7c4c..7f84ced 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -866,6 +866,13 @@ function system_schema() {
         'unsigned' => TRUE,
         'not null' => TRUE,
       ),
+      'uuid' => array(
+        'description' => 'The universally unique identifier for a file.',
+        'type' => 'varchar',
+        'length' => 36,
+        'not null' => TRUE,
+        'default' => '',
+      ),
       'uid' => array(
         'description' => 'The {users}.uid of the user who is associated with the file.',
         'type' => 'int',
@@ -929,6 +936,7 @@ function system_schema() {
       'uid' => array('uid'),
       'status' => array('status'),
       'timestamp' => array('timestamp'),
+      'uuid' => array('uuid'),
     ),
     'unique keys' => array(
       'uri' => array('uri'),
@@ -1925,6 +1933,30 @@ function system_update_8010() {
 }
 
 /**
+ * Create an uuid column for file_managed table.
+ *
+ * @ToDo: Batch generate uuids for all existing files without a uuid.
+ */
+function system_update_8011() {
+  db_add_field(
+    'file_managed',
+    'uuid',
+    array(
+      'description' => 'The universally unique identifier for a file.',
+      'type' => 'varchar',
+      'length' => 36,
+      'not null' => TRUE,
+      'default' => '',
+    ),
+    array(
+      'indexes' => array(
+        'uuid' => array('uuid'),
+      )
+    )
+  );
+}
+
+/**
  * @} End of "defgroup updates-7.x-to-8.x".
  * The next series of updates should start at 9000.
  */
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 73236f7..bdde02a 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -276,6 +276,7 @@ function system_entity_info() {
       'entity keys' => array(
         'id' => 'fid',
         'label' => 'filename',
+        'uuid' => 'uuid',
       ),
       'static cache' => FALSE,
     ),
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Term.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Term.php
index f036f18..418dc8f 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Term.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Term.php
@@ -22,6 +22,13 @@ class Term extends Entity {
   public $tid;
 
   /**
+   * The term UUID.
+   *
+   * @var integer
+   */
+  public $uuid;
+
+  /**
    * The taxonomy vocabulary ID this term belongs to.
    *
    * @var integer
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/TermStorageController.php b/core/modules/taxonomy/lib/Drupal/taxonomy/TermStorageController.php
index 09b0d80..c8da41d 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/TermStorageController.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/TermStorageController.php
@@ -9,6 +9,7 @@ namespace Drupal\taxonomy;
 
 use Drupal\entity\EntityInterface;
 use Drupal\entity\DatabaseStorageController;
+use Drupal\Component\Uuid\Uuid;
 
 /**
  * Defines a Controller class for taxonomy terms.
@@ -36,6 +37,11 @@ class TermStorageController extends DatabaseStorageController {
     if (!isset($entity->parent)) {
       $entity->parent = array(0);
     }
+
+    // Generate and add UUID.
+    $uuid = new Uuid();
+    $entity->uuid = $uuid->generate();
+
     return $entity;
   }
 
diff --git a/core/modules/taxonomy/taxonomy.install b/core/modules/taxonomy/taxonomy.install
index 14b6956..87dde70 100644
--- a/core/modules/taxonomy/taxonomy.install
+++ b/core/modules/taxonomy/taxonomy.install
@@ -32,6 +32,13 @@ function taxonomy_schema() {
         'not null' => TRUE,
         'description' => 'Primary Key: Unique term ID.',
       ),
+      'uuid' => array(
+        'description' => 'The universally unique identifier for a term.',
+        'type' => 'varchar',
+        'length' => 36,
+        'not null' => TRUE,
+        'default' => '',
+      ),
       'vid' => array(
         'type' => 'int',
         'unsigned' => TRUE,
@@ -85,6 +92,7 @@ function taxonomy_schema() {
       'taxonomy_tree' => array('vid', 'weight', 'name'),
       'vid_name' => array('vid', 'name'),
       'name' => array('name'),
+      'uuid' => array('uuid'),
     ),
   );
 
@@ -300,3 +308,27 @@ function taxonomy_update_8001() {
     }
   }
 }
+
+/**
+ * Create an uuid column for taxonomy_term_data table.
+ *
+ * @ToDo: Batch generate uuids for all existing terms without a uuid.
+ */
+function taxonomy_update_8002() {
+  db_add_field(
+    'taxonomy_term_data',
+    'uuid',
+    array(
+      'description' => 'The universally unique identifier for a term.',
+      'type' => 'varchar',
+      'length' => 36,
+      'not null' => TRUE,
+      'default' => '',
+    ),
+    array(
+      'indexes' => array(
+        'uuid' => array('uuid'),
+      )
+    )
+  );
+}
diff --git a/core/modules/taxonomy/taxonomy.module b/core/modules/taxonomy/taxonomy.module
index ba74a9a..ce93f07 100644
--- a/core/modules/taxonomy/taxonomy.module
+++ b/core/modules/taxonomy/taxonomy.module
@@ -120,6 +120,7 @@ function taxonomy_entity_info() {
         'id' => 'tid',
         'bundle' => 'vocabulary_machine_name',
         'label' => 'name',
+        'uuid' => 'uuid',
       ),
       'bundle keys' => array(
         'bundle' => 'machine_name',
diff --git a/core/modules/user/lib/Drupal/user/User.php b/core/modules/user/lib/Drupal/user/User.php
index 992923c..c503118 100644
--- a/core/modules/user/lib/Drupal/user/User.php
+++ b/core/modules/user/lib/Drupal/user/User.php
@@ -22,6 +22,13 @@ class User extends Entity {
   public $uid;
 
   /**
+   * The user UUID.
+   *
+   * @var integer
+   */
+  public $uuid;
+
+  /**
    * The unique user name.
    *
    * @var string
diff --git a/core/modules/user/lib/Drupal/user/UserStorageController.php b/core/modules/user/lib/Drupal/user/UserStorageController.php
index bde430c..32b53a0 100644
--- a/core/modules/user/lib/Drupal/user/UserStorageController.php
+++ b/core/modules/user/lib/Drupal/user/UserStorageController.php
@@ -10,6 +10,8 @@ namespace Drupal\user;
 use Drupal\entity\EntityInterface;
 use Drupal\entity\EntityMalformedException;
 use Drupal\entity\DatabaseStorageController;
+use Drupal\Component\Uuid\Uuid;
+
 
 /**
  * Controller class for users.
@@ -69,7 +71,14 @@ class UserStorageController extends DatabaseStorageController {
     // Users always have the authenticated user role.
     $values['roles'][DRUPAL_AUTHENTICATED_RID] = 'authenticated user';
 
-    return parent::create($values);
+    // Create user via parent class constructor.
+    $user = parent::create($values);
+
+    // Generate and add UUID.
+    $uuid = new Uuid();
+    $user->uuid = $uuid->generate();
+
+    return $user;
   }
 
   /**
diff --git a/core/modules/user/user.install b/core/modules/user/user.install
index 5ec57da..9b1956f 100644
--- a/core/modules/user/user.install
+++ b/core/modules/user/user.install
@@ -132,6 +132,13 @@ function user_schema() {
         'description' => 'Primary Key: Unique user ID.',
         'default' => 0,
       ),
+      'uuid' => array(
+        'description' => 'The universally unique identifier for a user.',
+        'type' => 'varchar',
+        'length' => 36,
+        'not null' => TRUE,
+        'default' => '',
+      ),
       'name' => array(
         'type' => 'varchar',
         'length' => 60,
@@ -244,6 +251,7 @@ function user_schema() {
       'created' => array('created'),
       'mail' => array('mail'),
       'picture' => array('picture'),
+      'uuid' => array('uuid'),
     ),
     'unique keys' => array(
       'name' => array('name'),
@@ -442,5 +450,29 @@ function user_update_8002() {
 }
 
 /**
+ * Create an uuid column for users table.
+ *
+ * @ToDo: Batch generate uuids for all existing users without a uuid.
+ */
+function user_update_8003() {
+  db_add_field(
+    'users',
+    'uuid',
+    array(
+      'description' => 'The universally unique identifier for a user.',
+      'type' => 'varchar',
+      'length' => 36,
+      'not null' => TRUE,
+      'default' => '',
+    ),
+    array(
+      'indexes' => array(
+        'uuid' => array('uuid'),
+      )
+    )
+  );
+}
+
+/**
  * @} End of "addtogroup updates-7.x-to-8.x".
  */
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 6f21c5c..ce441de 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -154,6 +154,7 @@ function user_entity_info() {
       'entity class' => 'Drupal\user\User',
       'entity keys' => array(
         'id' => 'uid',
+        'uuid' => 'uuid',
       ),
       'bundles' => array(
         'user' => array(