diff --git a/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php b/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
index f82b676..87d9d2a 100644
--- a/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/MTimeProtectedFastFileStorage.php
@@ -47,6 +47,13 @@ class MTimeProtectedFastFileStorage extends FileStorage {
   protected $secret;
 
   /**
+   * The maximum number of characters of the hash to use for uniqueness.
+   *
+   * @var int
+   */
+  protected $maxHashLength = 10;
+
+  /**
    * Constructs this MTimeProtectedFastFileStorage object.
    *
    * @param array $configuration
@@ -135,7 +142,8 @@ public function getFullPath($name, &$directory = NULL, &$directory_mtime = NULL)
     if (!isset($directory_mtime)) {
       $directory_mtime = file_exists($directory) ? filemtime($directory) : 0;
     }
-    return $directory . '/' . hash_hmac('sha256', $name, $this->secret . $directory_mtime) . '.php';
+    $hashed_name = substr(hash_hmac('sha256', $name, $this->secret . $directory_mtime), 0, $this->maxHashLength) . '.php';
+    return $directory . '/' . $hashed_name;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php b/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
index d2cf918..4d07643 100644
--- a/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
+++ b/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
@@ -44,6 +44,13 @@ class TwigPhpStorageCache implements \Twig_CacheInterface {
   protected $templateCacheFilenamePrefix;
 
   /**
+   * The maximum number of characters of the hash to use for uniqueness.
+   *
+   * @var int
+   */
+  protected $maxHashLength = 10;
+
+  /**
    * Store cache backend and other information internally.
    *
    * @param \Drupal\Core\Cache\CacheBackendInterface $cache
@@ -72,7 +79,7 @@ protected function storage() {
    * {@inheritdoc}
    */
   public function generateKey($name, $className) {
-    $hash = hash('sha256', $className);
+    $hash = substr(hash('sha256', $className), 0, $this->maxHashLength);
 
     if (strpos($name, '{# inline_template_start #}') === 0) {
       // $name is an inline template, and can have characters that are not valid
diff --git a/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php b/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
index 0bc52d0..8786d41 100644
--- a/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
+++ b/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
@@ -92,7 +92,7 @@ public function testInlineTemplate() {
 
     $cache = $environment->getCache();
     $class = $environment->getTemplateClass($name);
-    $expected = $hash . '_inline-template' . '_' . hash('sha256', $class);
+    $expected = $hash . '_inline-template_' . substr(hash('sha256', $class), 0, 10);
     $this->assertEqual($expected, $cache->generateKey($name, $class));
   }
 
diff --git a/core/tests/Drupal/Tests/Component/PhpStorage/MTimeProtectedFileStorageBase.php b/core/tests/Drupal/Tests/Component/PhpStorage/MTimeProtectedFileStorageBase.php
index 59944ff..9c02c15 100644
--- a/core/tests/Drupal/Tests/Component/PhpStorage/MTimeProtectedFileStorageBase.php
+++ b/core/tests/Drupal/Tests/Component/PhpStorage/MTimeProtectedFileStorageBase.php
@@ -82,7 +82,7 @@ public function testSecurity() {
       $expected_directory = $expected_root_directory . '/' . $name;
     }
     $directory_mtime = filemtime($expected_directory);
-    $expected_filename = $expected_directory . '/' . hash_hmac('sha256', $name, $this->secret . $directory_mtime) . '.php';
+    $expected_filename = $expected_directory . '/' . substr(hash_hmac('sha256', $name, $this->secret . $directory_mtime), 0, 10) . '.php';
 
     // Ensure the file exists and that it and the containing directory have
     // minimal permissions. fileperms() can return high bits unrelated to