From 0295c70f921f453cc88cb1c877d58708076d6d0c Mon Sep 17 00:00:00 2001
From: Harvey LV <harvey.lv@intel.com>
Date: Thu, 11 Sep 2025 10:31:51 +0800
Subject: [PATCH] Fix Windows file mode issue for key file updates

Change fopen mode from 'r+' to 'rb+' in demo.c to prevent
automatic line ending translation on Windows that corrupts
LMS key files during counter updates.
---
 demo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/demo.c b/demo.c
index 583fe13..d5a0860 100644
--- a/demo.c
+++ b/demo.c
@@ -147,7 +147,7 @@ bool do_rand( void *output, size_t len ) {
  */
 static bool update_private_key( unsigned char *private_key,
                                size_t len_private_key, void *filename) {
-    FILE *f = fopen( filename, "r+" );
+    FILE *f = fopen( filename, "rb+" );
     if (!f) {
         /* Open failed, possibly because the file didn't exist */
         f = fopen( filename, "wb" );