1 files changed, 1 insertions, 0 deletions

diff --git a/pssr.cpp b/pssr.cpp
index c2b21157..a4497059 100644
--- a/pssr.cpp
+++ b/pssr.cpp
@@ -2,6 +2,7 @@
 
 #include "pch.h"
 #include "pssr.h"
+#include <functional>
 
 NAMESPACE_BEGIN(CryptoPP)