1. TrueErase: Secure Deletion on Electronic Storage
Sarah Diesburg, Chris Meyers,
An-I Andy Wang
8/6/2018

2. Introduction
Many computer users believe that files have been completely erased when
Files are no longer visible
The trashcan is emptied
The partition is formatted
In reality, only icon to the file is deleted
Actual data remains

3. The Problem Decommissioned storage devices leak sensitive information
All headlines within the last year!

4. What is Secure Deletion?
Secure deletion means rendering files completely irrecoverable
No forensic analysis should be able to recover data from media

5. Secure Deletion Complications
Flash electronic storage can make it nearly impossible to erase files

6. Flash Characteristics
Locations must first be erased before new data can be written
But it can take awhile to erase a location
Locations can only be written or erased a small amount of times
The flash solution is to rotate locations for writes.

7. Flash Write Behavior
Flash management software rotates the usage of locations
Operating System
Flash 1 2 3 4 5 6 7 7 7

8. Flash Write Behavior
Flash management software rotates the usage of locations
Write gibberish
to 2
Operating System
Flash 1 2 3 4 5 6 7 8 8

9. Flash Write Behavior
Overwrites go to new location instead of original block
Dead data left behind until that location is erased
Write gibberish
to 2
Operating System
Flash 1 2 3 4 5 6 7 9 9

10. Ideal Secure Deletion Carry out deletion Allow fine-grained deletion
Work in acceptable amount of time

11. TrueErase Securely erase my file! Secure delete Operating System

12. TrueErase Flash Behavior
We can now tell the flash to erase locations
Securely delete 2
Operating System
Flash 1 2 3 4 5 6 7 12 12

13. TrueErase Flash Behavior
The location can be securely deleted!
Operating System
Erase!
Flash 1 2 3 4 5 6 7 13 13

14. Why is this hard? Flash management not easily changeable
Performance implications
Rotating the right locations
Operating systems (e.g. Windows) not designed for flash
Backward compatibility issues
Handling crashes during secure deletion
Correctness issues

15. Current Development – TrueErase

16. Current Development – TrueErase
Programming complete prototype
Flash secure deletion algorithm finished
Still working on OS expansions
Expected to be done for conference paper submission in mid-October

17. Questions?