diff --git a/src/requester.hpp b/src/requester.hpp
index 44dd7ee..5a19c2d 100644
--- a/src/requester.hpp
+++ b/src/requester.hpp
@@ -106,10 +106,10 @@
   static shared_ptr<Interest>
   genCertFetchInterest(const RequesterState& state);
 
-  shared_ptr<security::v2::Certificate>
+  static shared_ptr<security::v2::Certificate>
   onCertFetchResponse(const Data& reply);
 
-  void
+  static void
   endSession(RequesterState& state);
 
 private: