title: Windows BackupRead / BackupWrite and ACLs
body: <p>I have been trying to understand what should be the right way in using BackupRead and BackupWrite for backing up data on a computer and especially about restoring it reliably.</p>
  
  <p>Now I understand how to use the API and have been successful. However there's one thing that bothers me. 
  You can backup, beside the file content itself, any alternate data streams also the security information (ACLs).</p>
  
  <p>Now if I would store the ACL data for backup and then later, once the data needs to be restored on a different machine OR a newly setup machine what should I do with the SIDs which are related to the ACL?
  The SID is most likely no longer valid for the machine and how should the right user be selected?
  Now I am looking at this on a bigger scale let's say this is a computer with multiple users and hundreds or thousands of objects with different settings this would be mess to get the data restored with the security settings applied to them again.</p>
  
  <p>Is this something, if the user of the software wishes to backup the security settings, what the user has to take about himself and update them accordingly or what?</p>
  
  <p>Additionally BackupRead and BackupWrite will give me the raw binary data of those items which is not all too hard to use however obviously this API does not even intend to face this issue.</p>
  
  <p>Anyone has an idea how a backup application should handle this situation? What is your thought, or any pointers on guidelines for this specific topic?</p>
  
  <p>Thanks a lot.</p>