From c4b8166ffe2b9534a1d26ed984d3c8364154e394 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Tue, 25 Oct 2016 21:49:17 +0200
Subject: [PATCH] backup format v4: add backup_id field

Protect against feeding the user with the same VM but from older/newer
backup.
---
 common-tasks/backup-emergency-restore-v4.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/common-tasks/backup-emergency-restore-v4.md b/common-tasks/backup-emergency-restore-v4.md
index a2f5efc0..3b94a75a 100644
--- a/common-tasks/backup-emergency-restore-v4.md
+++ b/common-tasks/backup-emergency-restore-v4.md
@@ -64,12 +64,14 @@ Recovery - format version 3](/doc/backup-emergency-restore-v3/)
         encrypted=True
         compressed=True
         compression-filter=gzip
+        backup_id=20161020T123455-1234
   
  6. Verify the integrity and decrypt the `private.img` file which houses your data.
 
+        [user@restore ~]$ backup_id=20161020T123455-1234 # see backup-header above
         [user@restore ~]$ for f_enc in vm1/private.img.???.enc; do \
             f_dec=${f_enc%.enc}; \
-            echo "$f_dec!$backup_pass" | scrypt -P dec $f_enc $f_dec || break; \
+            echo "$backup_id!$f_dec!$backup_pass" | scrypt -P dec $f_enc $f_dec || break; \
             done
 
     **Note:** If the above fail, most likely your backup is corrupted, or been tampered with.