diff --git a/cryptdll.vcxproj b/cryptdll.vcxproj
index 88360ed5..2a65a6b9 100644
--- a/cryptdll.vcxproj
+++ b/cryptdll.vcxproj
@@ -212,6 +212,7 @@
     <ClCompile Include="gcm.cpp" />
     <ClCompile Include="gcm_simd.cpp" />
     <ClCompile Include="gf2n.cpp" />
+    <ClCompile Include="gf2n_simd.cpp" />
     <ClCompile Include="gfpcrypt.cpp" />
     <ClCompile Include="hex.cpp" />
     <ClCompile Include="hmac.cpp" />
diff --git a/cryptdll.vcxproj.filters b/cryptdll.vcxproj.filters
index 23bf3f49..a4951a76 100644
--- a/cryptdll.vcxproj.filters
+++ b/cryptdll.vcxproj.filters
@@ -98,6 +98,9 @@
     <ClCompile Include="gf2n.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="gf2n_simd.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
     <ClCompile Include="gfpcrypt.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
diff --git a/gf2n_simd.cpp b/gf2n_simd.cpp
index 395a3c04..1d4d933f 100644
--- a/gf2n_simd.cpp
+++ b/gf2n_simd.cpp
@@ -21,6 +21,8 @@
 #include "pch.h"
 #include "config.h"
 
+#ifndef CRYPTOPP_IMPORTS
+
 #include "gf2n.h"
 
 #if (CRYPTOPP_CLMUL_AVAILABLE)
@@ -608,3 +610,5 @@ GF2NT_233_Square_Reduce_POWER8(const word* pA, word* pC)
 #endif
 
 NAMESPACE_END
+
+#endif  // CRYPTOPP_IMPORTS
\ No newline at end of file