diff --git a/configure.ac b/configure.ac
index 0967069..3e672bc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -41,6 +41,7 @@ fi
 
 AC_TYPE_UINT16_T
 AC_TYPE_UINT32_T
+AC_CHECK_FUNCS(random)
 
 AC_MSG_CHECKING(for gnu make >= 3.81)
 make_okay=0
diff --git a/libqpdf/Pl_AES_PDF.cc b/libqpdf/Pl_AES_PDF.cc
index e3294ec..4b71501 100644
--- a/libqpdf/Pl_AES_PDF.cc
+++ b/libqpdf/Pl_AES_PDF.cc
@@ -7,6 +7,11 @@
 #include <qpdf/rijndael.h>
 #include <string>
 #include <stdlib.h>
+#include <qpdf/qpdf-config.h>
+#ifndef HAVE_RANDOM
+# define random rand
+# define srandom srand
+#endif
 
 Pl_AES_PDF::Pl_AES_PDF(char const* identifier, Pipeline* next,
 		       bool encrypt, unsigned char const key[key_size]) :