diff --git a/poppler/PDFDoc.h b/poppler/PDFDoc.h
index 328b0c7..f3e9f68 100644
--- a/poppler/PDFDoc.h
+++ b/poppler/PDFDoc.h
@@ -43,10 +43,10 @@
 #include "Page.h"
 #include "Annot.h"
 #include "OptionalContent.h"
+#include "Stream.h"
 
 class GooString;
 class BaseStream;
-enum CryptAlgorithm;
 class OutputDev;
 class Links;
 class LinkAction;
diff --git a/poppler/XRef.h b/poppler/XRef.h
index 2defc6c..9af4a13 100644
--- a/poppler/XRef.h
+++ b/poppler/XRef.h
@@ -36,6 +36,7 @@
 
 #include "goo/gtypes.h"
 #include "Object.h"
+#include "Stream.h"
 
 #include <vector>