diff --git a/include/wincrypt.h b/include/wincrypt.h
index 88b4b65d4c1..d8b116edf02 100644
--- a/include/wincrypt.h
+++ b/include/wincrypt.h
@@ -2046,6 +2046,12 @@ static const WCHAR MS_ENH_RSA_AES_PROV_XP_W[] = { 'M','i','c','r','o','s','o','f
 #define CRYPTPROTECT_AUDIT              0x0010
 #define CRYPTPROTECT_VERIFY_PROTECTION  0x0040
 
+/* Crypt{Protect,Unprotect}Memory */
+#define CRYPTPROTECTMEMORY_BLOCK_SIZE     16
+#define CRYPTPROTECTMEMORY_SAME_PROCESS   0x0000
+#define CRYPTPROTECTMEMORY_CROSS_PROCESS  0x0001
+#define CRYPTPROTECTMEMORY_SAME_LOGON     0x0002
+
 /* Blob Types */
 #define SIMPLEBLOB              0x1
 #define PUBLICKEYBLOB           0x6