diff --git a/core/lib/Drupal/Core/KeyValueStore/AbstractStorage.php b/core/lib/Drupal/Core/KeyValueStore/AbstractStorage.php
new file mode 100644
index 0000000..9111a84
--- /dev/null
+++ b/core/lib/Drupal/Core/KeyValueStore/AbstractStorage.php
@@ -0,0 +1,74 @@
+<?php
+/**
+ * @file
+ * Contains KeyValueStore\Storage\AbstracteBackend.
+ */
+
+namespace Drupal\Core\KeyValueStore;
+
+abstract class AbstractStorage implements KeyValueStoreInterface {
+
+  /**
+   * @var string
+   */
+  protected $collection;
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::__construct().
+   */
+  public function __construct($collection, array $options = array()) {
+    $this->collection = $collection;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::getCollectionName().
+   */
+  public function getCollectionName() {
+    return $this->collection;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::get().
+   */
+  public function get($key) {
+    $values = $this->getMultiple(array($key));
+    return reset($values);
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::getMultiple().
+   */
+  abstract public function getMultiple(array $keys);
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::getAll().
+   */
+  abstract public function getAll();
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::set().
+   */
+  abstract public function set($key, $value);
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::setMultiple().
+   */
+  public function setMultiple(array $data) {
+    foreach ($data as $key => $value) {
+      $this->set($key, $value);
+    }
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::delete().
+   */
+  public function delete($key) {
+    $this->deleteMultiple(array($key));
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::deleteMultiple().
+   */
+  abstract public function deleteMultiple(array $keys);
+
+}
diff --git a/core/lib/Drupal/Core/KeyValueStore/DatabaseStorage.php b/core/lib/Drupal/Core/KeyValueStore/DatabaseStorage.php
new file mode 100644
index 0000000..d1b206c
--- /dev/null
+++ b/core/lib/Drupal/Core/KeyValueStore/DatabaseStorage.php
@@ -0,0 +1,90 @@
+<?php
+
+/**
+ * @file
+ * Contains KeyValueStore\Storage\DatabaseBackend.
+ */
+
+namespace Drupal\Core\KeyValueStore;
+
+/**
+ * Defines a default key/value store implementation.
+ *
+ * This is Drupal's default key/value store implementation. It uses the database to store
+ * key/value data.
+ */
+class DatabaseStorage extends AbstractStorage {
+
+  /**
+   * Overrides KeyValueStore\Storage\AbstractStorage::__construct().
+   */
+  public function __construct($collection, array $options = array()) {
+    parent::__construct($collection, $options);
+    $this->table = isset($options['table']) ? $options['table'] : 'keyvalue';
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::getMultiple().
+   */
+  public function getMultiple(array $keys) {
+    try {
+      $result = db_query('SELECT name, value FROM {' . db_escape_table($this->table) . '} WHERE name IN (:keys) AND collection = :collection', array(':keys' => $keys, ':collection' => $this->collection))->fetchAllAssoc('name');
+      $values = array();
+      foreach ($keys as $key) {
+        if (isset($result[$key]) && ($value = unserialize($result[$key]->value))) {
+          $values[$key] = $value;
+        }
+      }
+      return $values;
+    }
+    catch (\Exception $e) {
+      // If the database is never going to be available, key/value requests should
+      // return FALSE in order to allow exception handling to occur.
+      return array();
+    }
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::getAll().
+   */
+  public function getAll() {
+    $result = db_query('SELECT name, value FROM {' . db_escape_table($this->table) . '} WHERE collection = :collection', array(':collection' => $this->collection));
+    $values = array();
+
+    foreach ($result as $item) {
+      if ($item) {
+        $values[$item->name] = unserialize($item->value);
+      }
+    }
+    return $values;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::set().
+   */
+  public function set($key, $value) {
+    db_merge($this->table)
+      ->key(array('name' => $key))
+      ->fields(array(
+        'collection' => $this->collection,
+        'value' => serialize($value),
+      ))
+      ->execute();
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::deleteMultiple().
+   */
+  public function deleteMultiple(array $keys) {
+    // Delete in chunks when a large array is passed.
+    do {
+      db_delete($this->table)
+        ->condition('name', array_splice($keys, 0, 1000))
+        ->condition('collection', $this->collection)
+        ->execute();
+    }
+    while (count($keys));
+  }
+
+}
+
diff --git a/core/lib/Drupal/Core/KeyValueStore/KeyValueStoreInterface.php b/core/lib/Drupal/Core/KeyValueStore/KeyValueStoreInterface.php
new file mode 100644
index 0000000..d4d7b6c
--- /dev/null
+++ b/core/lib/Drupal/Core/KeyValueStore/KeyValueStoreInterface.php
@@ -0,0 +1,98 @@
+<?php
+
+/**
+ * @file
+ * Contains KeyValueStore\Storage\StorageInterface.
+ */
+
+namespace Drupal\Core\KeyValueStore;
+
+
+/**
+ * Defines the interface for key/value store implementations.
+ */
+interface KeyValueStoreInterface {
+  /**
+   * Constructs a new key/value collection.
+   *
+   * @param string $collection
+   *   The collection for which the object is created.
+   * @param array $options
+   *   An associative array of options for the key/value storage collection.
+   */
+  public function __construct($collection, array $options = array());
+
+  /**
+   * Returns the name of this collection.
+   *
+   * @return string
+   *   The name of this collection.
+   */
+  public function getCollectionName();
+
+  /**
+   * Returns the stored value for a given key.
+   *
+   * @param $key
+   *   The key of the data to retrieve.
+   *
+   * @return mixed
+   *   The stored value, or FALSE if no value exists.
+   */
+  public function get($key);
+
+  /**
+   * Returns the stored key/value pairs for a given set of keys.
+   *
+   * @param array $keys
+   *   A list of keys to retrieve.
+   *
+   * @return array
+   *   An associative array of items successfully returned, indexed by key.
+   *   @todo What's returned for non-existing keys?
+   */
+  public function getMultiple(array $keys);
+
+  /**
+   * Returns all stored key/value pairs in the collection.
+   *
+   * @return array
+   *   An associative array containing all stored items in the collection.
+   */
+  public function getAll();
+
+  /**
+   * Saves a value for a given key.
+   *
+   * @param string $key
+   *   The key of the data to store.
+   * @param mixed $value
+   *   The data to store.
+   */
+  public function set($key, $value);
+
+  /**
+   * Saves key/value pairs.
+   *
+   * @param array $data
+   *   An associative array of key/value pairs.
+   */
+  public function setMultiple(array $data);
+
+  /**
+   * Deletes an item from the key/value store.
+   *
+   * @param string $key
+   *   The item name to delete.
+   */
+  public function delete($key);
+
+  /**
+   * Deletes multiple items from the key/value store.
+   *
+   * @param array $keys
+   *   A list of item names to delete.
+   */
+  public function deleteMultiple(array $keys);
+
+}
diff --git a/core/lib/Drupal/Core/KeyValueStore/MemoryStorage.php b/core/lib/Drupal/Core/KeyValueStore/MemoryStorage.php
new file mode 100644
index 0000000..c3524f4
--- /dev/null
+++ b/core/lib/Drupal/Core/KeyValueStore/MemoryStorage.php
@@ -0,0 +1,98 @@
+<?php
+
+/**
+ * @file
+ * Contains KeyValueStore\Storage\MemoryStorage.
+ */
+
+namespace Drupal\Core\KeyValueStore;
+
+/**
+ * Defines a default key/value store implementation.
+ *
+ * For speed reasons, this class does not use the AbstractStorage generic
+ * implementation.
+ */
+class MemoryStorage implements KeyValueStoreInterface {
+
+  /**
+   * @var array
+   */
+  protected $data = array();
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::__construct().
+   */
+  public function __construct($collection, array $options = array()) {
+    $this->collection = $collection;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::getCollectionName().
+   */
+  public function getCollectionName() {
+    return $this->collection;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::get().
+   */
+  public function get($key) {
+    return isset($this->data[$key]) ? $this->data[$key] : FALSE;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::getMultiple().
+   */
+  public function getMultiple(array $keys) {
+    $results = array();
+    // Foreach only needs to traverse $keys once, the PHP implementation
+    // array_intersect_key(array_flip(array_values($keys)), $this->data);
+    // would be slower.
+    foreach ($keys as $key) {
+      if (isset($this->data[$key])) {
+        $results[$key] = $this->data[$key];
+      }
+    }
+    return $results;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::getAll().
+   */
+  public function getAll() {
+    return $this->data;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::set().
+   */
+  public function set($key, $value) {
+    $this->data[$key] = $value;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::setMultiple().
+   */
+  public function setMultiple(array $data) {
+    $this->data = $data + $this->data;
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::delete().
+   */
+  public function delete($key) {
+    unset($this->data[$key]);
+  }
+
+  /**
+   * Implements KeyValueStore\Storage\StorageInterface::deleteMultiple().
+   */
+  public function deleteMultiple(array $keys) {
+    foreach ($keys as $key) {
+      unset($this->data[$key]);
+    }
+  }
+
+}
+
diff --git a/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/DatabaseStorageTest.php b/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/DatabaseStorageTest.php
new file mode 100644
index 0000000..9b3f6ad
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/DatabaseStorageTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Drupal\system\Tests\KeyValueStore;
+
+class DatabaseStorageTest extends StorageTestBase {
+
+  static function getInfo() {
+    return array(
+      'name' => 'Database Storage',
+      'description' => 'Test the key-value database storage.',
+      'group' => 'Key-value store'
+    );
+  }
+
+  protected function setUp() {
+    parent::setUp();
+    module_load_install('system');
+    $schema = system_schema();
+    db_create_table('keyvalue', $schema['keyvalue']);
+  }
+}
diff --git a/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/MemoryStorageTest.php b/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/MemoryStorageTest.php
new file mode 100644
index 0000000..d3db3bc
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/MemoryStorageTest.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Drupal\system\Tests\KeyValueStore;
+
+class MemoryStorageTest extends StorageTestBase {
+
+  static function getInfo() {
+    return array(
+      'name' => 'Memory Storage',
+      'description' => 'Test the key-value memory storage.',
+      'group' => 'Key-value store'
+    );
+  }
+
+}
diff --git a/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/StorageTestBase.php b/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/StorageTestBase.php
new file mode 100644
index 0000000..8fb38a0
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/StorageTestBase.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace Drupal\system\Tests\KeyValueStore;
+
+use Drupal\simpletest\UnitTestBase;
+
+class StorageTestBase extends UnitTestBase {
+  protected function setUp() {
+    parent::setUp();
+    $class = explode('\\', get_class($this));
+    $this->collection = end($class);
+    $storageClass = '\\Drupal\\Core\\KeyValueStore\\' . substr($this->collection, 0, -4);
+    $this->kv = new $storageClass($this->collection);
+  }
+
+  public function testSetGet() {
+    $this->assertEqual($this->kv->getCollectionName(), $this->collection);
+    // get-set test.
+    $this->kv->set('foo', 'bar');
+    $this->assertEqual('bar', $this->kv->get('foo'));
+    $this->kv->delete('foo');
+    $this->assertFalse($this->kv->get('foo'));
+
+    // multiple test.
+    $values = array('foo' => 'bar', 'baz' => 'qux');
+    $this->kv->setMultiple($values);
+    $result = $this->kv->getMultiple(array('foo', 'baz'));
+    $this->assertEqual($values, $result);
+    $result = $this->kv->getAll();
+    // $result might not equal to $values, the order is not defined for
+    // getAll().
+    $this->assertEqual(count($result), count($values));
+    foreach ($result as $key => $value) {
+      $this->assertEqual($values[$key], $value);
+    }
+    $this->kv->deleteMultiple(array_keys($values));
+    $this->assertFalse($this->kv->get('foo'));
+    $this->assertFalse($this->kv->get('bar'));
+    $this->assertFalse($this->kv->getMultiple(array('foo', 'baz')));
+  }
+}
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index ac983aa..87b3150 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -549,6 +549,33 @@ function system_schema() {
     ),
     'primary key' => array('name'),
   );
+  $schema['keyvalue'] = array(
+    'description' => 'Generic key-value storage table.',
+    'fields' => array(
+      'name' => array(
+       'description' => 'The key.',
+       'type' => 'varchar',
+       'length' => 128,
+       'not null' => TRUE,
+       'default' => '',
+      ),
+      'collection' => array(
+        'description' => 'The collection of the variable.',
+        'type' => 'varchar',
+        'length' => 128,
+        'not null' => TRUE,
+        'default' => '',
+      ),
+      'value' => array(
+        'description' => 'The value.',
+        'type' => 'blob',
+        'not null' => TRUE,
+        'size' => 'big',
+        'translatable' => TRUE,
+      ),
+    ),
+    'primary key' => array('collection', 'name'),
+  );
 
   $schema['actions'] = array(
     'description' => 'Stores action information.',