diff --git a/core/lib/Drupal/Core/Config/ConfigInstaller.php b/core/lib/Drupal/Core/Config/ConfigInstaller.php
index 1293574..b34dc80 100644
--- a/core/lib/Drupal/Core/Config/ConfigInstaller.php
+++ b/core/lib/Drupal/Core/Config/ConfigInstaller.php
@@ -306,7 +306,10 @@ protected function createConfiguration($collection, array $config_to_create) {
           $entity = $entity_storage->createFromStorageRecord($new_config->get());
         }
         if ($entity->isInstallable()) {
-          $entity->trustData()->set('defaultConfigHash', Crypt::hashBase64(serialize($new_config->get())))->save();
+          $entity
+            ->set('default_config_hash', Crypt::hashBase64(serialize($new_config->get())))
+            ->trustData()
+            ->save();
         }
       }
       else {
diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
index 0d464c5..70144d2 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
@@ -106,7 +106,7 @@
   /**
    * @var string
    */
-  protected $defaultConfigHash = '';
+  protected $default_config_hash = '';
 
   /**
    * Trust supplied data and not use configuration schema on save.
@@ -301,8 +301,8 @@ public function toArray() {
     if (empty($this->third_party_settings)) {
       unset($properties['third_party_settings']);
     }
-    if (empty($this->defaultConfigHash)) {
-      unset($properties['defaultConfigHash']);
+    if (empty($this->default_config_hash)) {
+      unset($properties['default_config_hash']);
     }
     return $properties;
   }
diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
index 8fabf36..b29f803 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
@@ -157,7 +157,7 @@ public function getPropertiesToExport() {
           'status' => 'status',
           'dependencies' => 'dependencies',
           'third_party_settings' => 'third_party_settings',
-          'defaultConfigHash' => 'default_config_hash',
+          'default_config_hash' => 'default_config_hash',
         ];
         foreach ($this->config_export as $property => $name) {
           if (is_numeric($property)) {
diff --git a/core/modules/config/src/Tests/ConfigSchemaTest.php b/core/modules/config/src/Tests/ConfigSchemaTest.php
index a94e26a..3c7980c 100644
--- a/core/modules/config/src/Tests/ConfigSchemaTest.php
+++ b/core/modules/config/src/Tests/ConfigSchemaTest.php
@@ -179,6 +179,8 @@ function testSchemaMapping() {
     $expected['mapping']['third_party_settings']['type'] = 'sequence';
     $expected['mapping']['third_party_settings']['label'] = 'Third party settings';
     $expected['mapping']['third_party_settings']['sequence']['type'] = '[%parent.%parent.%type].third_party.[%key]';
+    $expected['mapping']['default_config_hash']['type'] = 'string';
+    $expected['mapping']['default_config_hash']['label'] = 'Default configuration hash';
     $expected['type'] = 'image.style.*';
 
     $this->assertEqual($definition, $expected);
diff --git a/core/tests/Drupal/KernelTests/AssertConfigTrait.php b/core/tests/Drupal/KernelTests/AssertConfigTrait.php
index 24d393e..8489ae7 100644
--- a/core/tests/Drupal/KernelTests/AssertConfigTrait.php
+++ b/core/tests/Drupal/KernelTests/AssertConfigTrait.php
@@ -79,6 +79,10 @@ protected function assertConfigDiff(Diff $result, $config_name, array $skipped_c
             if (strpos($closing, 'uuid: ') === 0)  {
               continue;
             }
+            // The UUIDs don't exist in the default config.
+            if (strpos($closing, 'default_config_hash: ') === 0)  {
+              continue;
+            }
             throw new \Exception($config_name . ': ' . var_export($op, TRUE));
           }
           break;
diff --git a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityTypeTest.php b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityTypeTest.php
index 97bf172..44eae9a 100644
--- a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityTypeTest.php
+++ b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityTypeTest.php
@@ -163,6 +163,7 @@ public function providerGetPropertiesToExport() {
         'status' => 'status',
         'dependencies' => 'dependencies',
         'third_party_settings' => 'third_party_settings',
+        'default_config_hash' => 'default_config_hash',
         'id' => 'id',
         'custom_property' => 'customProperty',
       ],