diff --git a/lib/notification_factory/renderer.rb b/lib/notification_factory/renderer.rb
index e8d4a8697..f15179d96 100644
--- a/lib/notification_factory/renderer.rb
+++ b/lib/notification_factory/renderer.rb
@@ -139,7 +139,7 @@ examples how to use
   end
 
   def data_key_valid?(key)
-    return false if key =~ /`|\.(|\s*)(save|destroy|delete|remove|drop|update|create|new|all|where|find)/i && key !~ /(update|create)d_at/i
+    return false if key =~ /`|\.(|\s*)(save|destroy|delete|remove|drop|update|create|new|all|where|find|raise|dump|rollback|freeze)/i && key !~ /(update|create)d_(at|by)/i
     true
   end
 
diff --git a/test/unit/notification_factory_renderer_test.rb b/test/unit/notification_factory_renderer_test.rb
index d091afeec..a09c73015 100644
--- a/test/unit/notification_factory_renderer_test.rb
+++ b/test/unit/notification_factory_renderer_test.rb
@@ -9,7 +9,7 @@ class NotificationFactoryRendererTest < ActiveSupport::TestCase
   end
 
   group        = Group.new(name: 'Users')
-  owner        = User.new(firstname: 'Notification<b>xxx</b>', lastname: 'Agent1<b>yyy</b>')
+  owner        = User.new(firstname: 'Owner<b>xxx</b>', lastname: 'Agent1<b>yyy</b>')
   current_user = User.new(firstname: 'CurrentUser<b>xxx</b>', lastname: 'Agent2<b>yyy</b>')
   recipient    = User.new(firstname: 'Recipient<b>xxx</b>', lastname: 'Customer1<b>yyy</b>')
   state        = Ticket::State.new(name: 'new')
@@ -19,6 +19,8 @@ class NotificationFactoryRendererTest < ActiveSupport::TestCase
     group: group,
     owner: owner,
     state: state,
+    created_by: current_user,
+    updated_by: current_user,
     created_at: Time.zone.parse('2016-11-12 12:00:00 UTC'),
     updated_at: Time.zone.parse('2016-11-12 14:00:00 UTC'),
   )
@@ -56,6 +58,16 @@ class NotificationFactoryRendererTest < ActiveSupport::TestCase
     ).render
     assert_equal(ticket.created_at.to_s, result)
 
+    template = "\#{ticket.created_by.firstname}"
+    result = described_class.new(
+      {
+        ticket: ticket,
+      },
+      'en-us',
+      template,
+    ).render
+    assert_equal('CurrentUser&lt;b&gt;xxx&lt;/b&gt;', result)
+
     template = "\#{ticket.updated_at}"
     result = described_class.new(
       {
@@ -66,6 +78,26 @@ class NotificationFactoryRendererTest < ActiveSupport::TestCase
     ).render
     assert_equal(ticket.updated_at.to_s, result)
 
+    template = "\#{ticket.updated_by.firstname}"
+    result = described_class.new(
+      {
+        ticket: ticket,
+      },
+      'en-us',
+      template,
+    ).render
+    assert_equal('CurrentUser&lt;b&gt;xxx&lt;/b&gt;', result)
+
+    template = "\#{ticket.owner.firstname}"
+    result = described_class.new(
+      {
+        ticket: ticket,
+      },
+      'en-us',
+      template,
+    ).render
+    assert_equal('Owner&lt;b&gt;xxx&lt;/b&gt;', result)
+
     template = "\#{ticket. title}"
     result = described_class.new(
       {