diff --git a/src/cryptlib/asn.cpp b/src/cryptlib/asn.cpp
index a0eb77a..d5265e6 100644
--- a/src/cryptlib/asn.cpp
+++ b/src/cryptlib/asn.cpp
@@ -4,6 +4,7 @@
 #include "asn.h"
 #include "misc.h"
 #include <stdlib.h>
+#include <stdio.h>
 
 unsigned int DERLengthEncode(unsigned int length, byte *output)
 {