diff --git a/dlls/wintrust/register.c b/dlls/wintrust/register.c
index 7037f09083a..1f1fc86b27a 100644
--- a/dlls/wintrust/register.c
+++ b/dlls/wintrust/register.c
@@ -679,6 +679,16 @@ static void WINTRUST_RegisterGenChainVerify(void)
     WintrustAddActionID(&ProvGUID, 0, &ProvInfo);
 }
 
+/***********************************************************************
+ *              WintrustAddDefaultForUsage (WINTRUST.@)
+ */
+BOOL WINAPI WintrustAddDefaultForUsage(const CHAR *pszUsageOID,
+                                       CRYPT_PROVIDER_REGDEFUSAGE *psDefUsage)
+{
+     FIXME("(%s %p) stub\n", debugstr_a(pszUsageOID), psDefUsage);
+     return FALSE;
+}
+
 /***********************************************************************
  *              DllRegisterServer (WINTRUST.@)
  */
diff --git a/dlls/wintrust/wintrust.spec b/dlls/wintrust/wintrust.spec
index f7a4221bdde..5335605ff6c 100644
--- a/dlls/wintrust/wintrust.spec
+++ b/dlls/wintrust/wintrust.spec
@@ -111,7 +111,7 @@
 @ stdcall WinVerifyTrust(long ptr ptr)
 @ stdcall WinVerifyTrustEx(long ptr ptr)
 @ stdcall WintrustAddActionID(ptr long ptr)
-@ stub WintrustAddDefaultForUsage
+@ stdcall WintrustAddDefaultForUsage(ptr ptr)
 @ stub WintrustCertificateTrust
 @ stub WintrustGetDefaultForUsage
 @ stdcall WintrustGetRegPolicyFlags(ptr)
diff --git a/include/wintrust.h b/include/wintrust.h
index b6c8785e017..9c4f7c91f81 100644
--- a/include/wintrust.h
+++ b/include/wintrust.h
@@ -135,6 +135,15 @@ typedef struct _CRYPT_REGISTER_ACTIONID
     CRYPT_TRUST_REG_ENTRY sCleanupProvider;
 } CRYPT_REGISTER_ACTIONID, *PCRYPT_REGISTER_ACTIONID;
 
+typedef struct _CRYPT_PROVIDER_REGDEFUSAGE
+{
+    DWORD cbStruct;
+    GUID  *pgActionID;
+    WCHAR *pwszDllName;
+    char  *pwszLoadCallbackDataFunctionName;
+    char  *pwszFreeCallbackDataFunctionName;
+} CRYPT_PROVIDER_REGDEFUSAGE, *PCRYPT_PROVIDER_REGDEFUSAGE;
+
 typedef struct _CRYPT_PROVUI_DATA {
     DWORD cbStruct;
     DWORD dwFinalError;
@@ -316,6 +325,7 @@ static const WCHAR WT_PROVIDER_CERTTRUST_FUNCTION[] = \
 BOOL      WINAPI WintrustAddActionID(GUID*,DWORD,CRYPT_REGISTER_ACTIONID*);
 BOOL      WINAPI WintrustRemoveActionID(GUID*);
 BOOL      WINAPI WintrustLoadFunctionPointers(GUID*,CRYPT_PROVIDER_FUNCTIONS*);
+BOOL      WINAPI WintrustAddDefaultForUsage(const CHAR*,CRYPT_PROVIDER_REGDEFUSAGE*);
 void      WINAPI WintrustGetRegPolicyFlags(DWORD*);
 LONG      WINAPI WinVerifyTrust(HWND,GUID*,LPVOID);
 HRESULT   WINAPI WinVerifyTrustEx(HWND,GUID*,WINTRUST_DATA*);