Part of proper data and device (asset) management is the secure deletion (sanitization) and destruction of data when it is no longer required for a project and not suitable for preservation or subject to retention or archiving requirements.

1. Determine whether your data should be preserved or archived?
   • Research data: Preservation – Research Data Management.
   • Administrative data: University of Toronto File Plan.
2. Determine the classification of data stored on the device: Data Classification.
3. For confidential, sensitive, restricted, or regulated data (Level 3 or 4):
   • Recoverability (after deletion): Unrecoverable, if stored on an encrypted device.
   • Electronic:
     • Windows
       • File: Use SDelete or Eraser.
       • Device: See Cross-platform options.
     • MacOS
       • File: Use srm command.
       • Device: Apple support (choose “most secure” under “security options”).
     • Linux
       • File: Use shred -u command.
       • Device: Use shred -vfz command.
     • Cross-platform
       • Device: Your motherboard or drive manufacturer might provide a proprietary sanitization utility, Parted Magic, or DBAN.
     • Cloud service
       • Contact provider regarding secure data deletion pipeline.
   • Physical: Commercial shredding.
     • Ensure that you receive a Certificate of Destruction for your records.
4. For non-sensitive, non-public data (Level 2):
   • Recoverability (after deletion): Recoverable with difficulty
   • Electronic:
     • Windows
       • File: Use SDelete.
       • Device: Windows support (do NOT perform a “quick format”).
     • MacOS
       • File: Delete file and empty Trash.
       • Device: Apple support (do NOT select “fastest” under “security options”).
     • Linux
       • File: Use shred -u command.
       • Device: Use shred -vfz command.
     • Cloud service
       • Contact provider regarding secure data deletion pipeline.
   • Physical: Office or commercial shredding.
5. For public data (Level 1):
   • Recoverability (after deletion): Data could be recovered with little difficulty.
   • Electronic:
     • Windows
       • File: Delete file and empty Recycle Bin.
       • Device: Windows support.
     • MacOS
       • File: Delete file and empty Trash.
       • Device: Apple support.
     • Linux
       • File: Delete file or use rm command.
       • Device: Umount device and use mkfs command.
     • Cloud service
       • Delete file within platform; wait for recovery period to expire.
   • Physical: Recyle, if appropriate.