diff --git a/src/encoding/cryptopp/asn_ext.hpp b/src/encoding/cryptopp/asn_ext.hpp
index bbfe733..0d64d40 100644
--- a/src/encoding/cryptopp/asn_ext.hpp
+++ b/src/encoding/cryptopp/asn_ext.hpp
@@ -19,6 +19,8 @@
 #include "../../common.hpp"
 #include "../../security/cryptopp.hpp"
 
+#include "../../util/time.hpp"
+
 namespace ndn {
 
 size_t