diff --git a/dlls/credui/credui.spec b/dlls/credui/credui.spec
index d32a6020365..891416c0039 100644
--- a/dlls/credui/credui.spec
+++ b/dlls/credui/credui.spec
@@ -15,3 +15,4 @@
 @ stub DllGetClassObject
 @ stub DllRegisterServer
 @ stub DllUnregisterServer
+@ stdcall SspiPromptForCredentialsW(wstr ptr long wstr ptr ptr ptr long)
diff --git a/dlls/credui/credui_main.c b/dlls/credui/credui_main.c
index c7b2da44039..beb3c586c92 100644
--- a/dlls/credui/credui_main.c
+++ b/dlls/credui/credui_main.c
@@ -25,6 +25,8 @@
 #include "winnt.h"
 #include "winuser.h"
 #include "wincred.h"
+#include "rpc.h"
+#include "sspi.h"
 #include "commctrl.h"
 
 #include "credui_resources.h"
@@ -558,7 +560,8 @@ static BOOL find_existing_credential(const WCHAR *target, WCHAR *username, ULONG
     if (!CredEnumerateW(target, 0, &count, &credentials)) return FALSE;
     for (i = 0; i < count; i++)
     {
-        if (credentials[i]->Type != CRED_TYPE_DOMAIN_PASSWORD)
+        if (credentials[i]->Type != CRED_TYPE_DOMAIN_PASSWORD &&
+            credentials[i]->Type != CRED_TYPE_GENERIC)
         {
             FIXME("no support for type %u credentials\n", credentials[i]->Type);
             continue;
@@ -849,3 +852,80 @@ BOOL WINAPI CredUIInitControls(void)
     FIXME("() stub\n");
     return TRUE;
 }
+
+/******************************************************************************
+ * SspiPromptForCredentialsW [CREDUI.@]
+ */
+ULONG SEC_ENTRY SspiPromptForCredentialsW( PCWSTR target, void *info,
+                                           DWORD error, PCWSTR package,
+                                           PSEC_WINNT_AUTH_IDENTITY_OPAQUE input_id,
+                                           PSEC_WINNT_AUTH_IDENTITY_OPAQUE *output_id,
+                                           BOOL *save, DWORD sspi_flags )
+{
+    static const WCHAR basicW[] = {'B','a','s','i','c',0};
+    static const WCHAR ntlmW[] = {'N','T','L','M',0};
+    static const WCHAR negotiateW[] = {'N','e','g','o','t','i','a','t','e',0};
+    WCHAR username[CREDUI_MAX_USERNAME_LENGTH + 1] = {0};
+    WCHAR password[CREDUI_MAX_PASSWORD_LENGTH + 1] = {0};
+    DWORD len_username = sizeof(username) / sizeof(username[0]);
+    DWORD len_password = sizeof(password) / sizeof(password[0]);
+    DWORD ret, flags;
+    CREDUI_INFOW *cred_info = info;
+
+    FIXME( "(%s, %p, %u, %s, %p, %p, %p, %x) stub\n", debugstr_w(target), info,
+           error, debugstr_w(package), input_id, output_id, save, sspi_flags );
+
+    if (!target) return ERROR_INVALID_PARAMETER;
+    if (!package || (strcmpiW( package, basicW ) && strcmpiW( package, ntlmW ) &&
+                     strcmpiW( package, negotiateW )))
+    {
+        FIXME( "package %s not supported\n", debugstr_w(package) );
+        return ERROR_NO_SUCH_PACKAGE;
+    }
+    if (input_id)
+    {
+        FIXME( "input identity not supported\n" );
+        return ERROR_CALL_NOT_IMPLEMENTED;
+    }
+
+    flags = CREDUI_FLAGS_ALWAYS_SHOW_UI | CREDUI_FLAGS_GENERIC_CREDENTIALS;
+
+    if (sspi_flags & SSPIPFC_CREDPROV_DO_NOT_SAVE)
+        flags |= CREDUI_FLAGS_DO_NOT_PERSIST;
+
+    if (!(sspi_flags & SSPIPFC_NO_CHECKBOX))
+        flags |= CREDUI_FLAGS_SHOW_SAVE_CHECK_BOX;
+
+    find_existing_credential( target, username, len_username, password, len_password );
+
+    if (!(ret = CredUIPromptForCredentialsW( cred_info, target, NULL, error, username,
+                                             len_username, password, len_password, save, flags )))
+    {
+        SEC_WINNT_AUTH_IDENTITY_W *id;
+        DWORD size = sizeof(*id);
+        WCHAR *ptr;
+
+        len_username = strlenW( username );
+        len_password = strlenW( password );
+
+        size += (len_username + 1) * sizeof(WCHAR);
+        size += (len_password + 1) * sizeof(WCHAR);
+        if (!(id = HeapAlloc( GetProcessHeap(), 0, size ))) return ERROR_OUTOFMEMORY;
+        ptr = (WCHAR *)(id + 1);
+
+        memcpy( ptr, username, (len_username + 1) * sizeof(WCHAR) );
+        id->User           = ptr;
+        id->UserLength     = len_username;
+        ptr += len_username + 1;
+        id->Domain         = NULL;
+        id->DomainLength   = 0;
+        memcpy( ptr, password, (len_password + 1) * sizeof(WCHAR) );
+        id->Password       = ptr;
+        id->PasswordLength = len_password;
+        id->Flags          = 0;
+
+        *output_id = id;
+    }
+
+    return ret;
+}
diff --git a/dlls/credui/tests/credui.c b/dlls/credui/tests/credui.c
index 18fc5bc616f..1f5aa021541 100644
--- a/dlls/credui/tests/credui.c
+++ b/dlls/credui/tests/credui.c
@@ -23,9 +23,17 @@
 #include "windef.h"
 #include "winbase.h"
 #include "wincred.h"
+#include "sspi.h"
 
 #include "wine/test.h"
 
+static SECURITY_STATUS (SEC_ENTRY *pSspiEncodeAuthIdentityAsStrings)
+    (PSEC_WINNT_AUTH_IDENTITY_OPAQUE,PCWSTR*,PCWSTR*,PCWSTR*);
+static void (SEC_ENTRY *pSspiFreeAuthIdentity)
+    (PSEC_WINNT_AUTH_IDENTITY_OPAQUE);
+static ULONG (SEC_ENTRY *pSspiPromptForCredentialsW)
+    (PCWSTR,void*,ULONG,PCWSTR,PSEC_WINNT_AUTH_IDENTITY_OPAQUE,PSEC_WINNT_AUTH_IDENTITY_OPAQUE*,int*,ULONG);
+
 static void test_CredUIPromptForCredentials(void)
 {
     static const WCHAR wszServerName[] = {'W','i','n','e','T','e','s','t',0};
@@ -140,7 +148,71 @@ static void test_CredUIPromptForCredentials(void)
     }
 }
 
+static void test_SspiPromptForCredentials(void)
+{
+    static const WCHAR targetW[] = {'S','s','p','i','T','e','s','t',0};
+    static const WCHAR basicW[] = {'b','a','s','i','c',0};
+    ULONG ret;
+    SECURITY_STATUS status;
+    CREDUI_INFOW info;
+    PSEC_WINNT_AUTH_IDENTITY_OPAQUE id;
+    const WCHAR *username, *domain, *creds;
+    int save;
+
+    if (!pSspiPromptForCredentialsW || !pSspiFreeAuthIdentity)
+    {
+        win_skip( "SspiPromptForCredentialsW is missing\n" );
+        return;
+    }
+
+    info.cbSize         = sizeof(info);
+    info.hwndParent     = NULL;
+    info.pszMessageText = targetW;
+    info.pszCaptionText = basicW;
+    info.hbmBanner      = NULL;
+    ret = pSspiPromptForCredentialsW( NULL, &info, 0, basicW, NULL, &id, &save, 0 );
+    ok( ret == ERROR_INVALID_PARAMETER, "got %u\n", ret );
+
+    ret = pSspiPromptForCredentialsW( targetW, &info, 0, NULL, NULL, &id, &save, 0 );
+    ok( ret == ERROR_NO_SUCH_PACKAGE, "got %u\n", ret );
+
+    if (winetest_interactive)
+    {
+        id = NULL;
+        save = -1;
+        ret = pSspiPromptForCredentialsW( targetW, &info, 0, basicW, NULL, &id, &save, 0 );
+        ok( ret == ERROR_SUCCESS || ret == ERROR_CANCELLED, "got %u\n", ret );
+        if (ret == ERROR_SUCCESS)
+        {
+            ok( id != NULL, "id not set\n" );
+            ok( save == TRUE || save == FALSE, "got %d\n", save );
+
+            username = creds = NULL;
+            domain = (const WCHAR *)0xdeadbeef;
+            status = pSspiEncodeAuthIdentityAsStrings( id, &username, &domain, &creds );
+            ok( status == SEC_E_OK, "got %u\n", status );
+            ok( username != NULL, "username not set\n" );
+            ok( domain == NULL, "domain not set\n" );
+            ok( creds != NULL, "creds not set\n" );
+            pSspiFreeAuthIdentity( id );
+        }
+    }
+}
+
 START_TEST(credui)
 {
+    HMODULE hcredui = GetModuleHandleA( "credui.dll" ), hsecur32 = LoadLibraryA( "secur32.dll" );
+
+    if (hcredui)
+        pSspiPromptForCredentialsW = (void *)GetProcAddress( hcredui, "SspiPromptForCredentialsW" );
+    if (hsecur32)
+    {
+        pSspiEncodeAuthIdentityAsStrings = (void *)GetProcAddress( hsecur32, "SspiEncodeAuthIdentityAsStrings" );
+        pSspiFreeAuthIdentity = (void *)GetProcAddress( hsecur32, "SspiFreeAuthIdentity" );
+    }
+
     test_CredUIPromptForCredentials();
+    test_SspiPromptForCredentials();
+
+    FreeLibrary( hsecur32 );
 }
diff --git a/include/wincred.h b/include/wincred.h
index d0a75a72bfc..f238c0569cb 100644
--- a/include/wincred.h
+++ b/include/wincred.h
@@ -184,6 +184,7 @@ typedef struct _BINARY_BLOB_CREDENTIAL_INFO
 #define CRED_MAX_ATTRIBUTES                 64
 
 #define CRED_MAX_BLOB_SIZE                  512
+#define CRED_MAX_CREDENTIAL_BLOB_SIZE       (5 * CRED_MAX_BLOB_SIZE)
 
 #define CREDUI_MAX_MESSAGE_LENGTH 32767
 #define CREDUI_MAX_CAPTION_LENGTH 128