diff --git a/include/WinStd/Crypt.h b/include/WinStd/Crypt.h
index b2da7526..468b57da 100644
--- a/include/WinStd/Crypt.h
+++ b/include/WinStd/Crypt.h
@@ -511,7 +511,7 @@ namespace winstd
         ///
         /// \sa [CertGetCertificateChain function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa376078.aspx)
         ///
-        inline bool create(_In_opt_ HCERTCHAINENGINE hChainEngine, _In_ PCCERT_CONTEXT pCertContext, _In_opt_ LPFILETIME pTime, _In_opt_ HCERTSTORE hAdditionalStore, _In_ PCERT_CHAIN_PARA pChainPara, _In_ DWORD dwFlags, __reserved LPVOID pvReserved)
+        inline bool create(_In_opt_ HCERTCHAINENGINE hChainEngine, _In_ PCCERT_CONTEXT pCertContext, _In_opt_ LPFILETIME pTime, _In_opt_ HCERTSTORE hAdditionalStore, _In_ PCERT_CHAIN_PARA pChainPara, _In_ DWORD dwFlags, __reserved LPVOID pvReserved = NULL)
         {
             handle_type h;
             if (CertGetCertificateChain(hChainEngine, pCertContext, pTime, hAdditionalStore, pChainPara, dwFlags, pvReserved, &h)) {
@@ -625,7 +625,7 @@ namespace winstd
         ///
         /// \sa [CryptAcquireContext function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa379886.aspx)
         ///
-        inline bool create(_In_opt_ LPCTSTR szContainer, _In_opt_ LPCTSTR szProvider, _In_ DWORD dwProvType, _In_ DWORD dwFlags)
+        inline bool create(_In_opt_ LPCTSTR szContainer, _In_opt_ LPCTSTR szProvider, _In_ DWORD dwProvType, _In_ DWORD dwFlags = 0)
         {
             handle_type h;
             if (CryptAcquireContext(&h, szContainer, szProvider, dwProvType, dwFlags)) {