Blog Post 11: Privacy Blog 1

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Complete Delete: In Practice, Clicking ‘Delete’ Rarely Deletes. Should it?

What is the goal of this case study?

This case study touches on digital histories, and how rare it is for files to truly be deleted. It compares common file deletion techniques, and discusses the rights and laws around file deletion, and the pros and cons of full deletion.

Discussion:

Questions:

1. Propose approaches for informing users of the existence of remnant data on their systems.
   • Because this data is there until we erase the blocks of memory, it would be vital to tell the users when their data could be retrieved. To do this, we could make use of the table in the FAT file system - as we ‘delete’ data, we can simply tell the user the data is still there, until we’ve replaced that slot in the table, by exposing the table. This would allow users to have a better sense of what is being stored on their computer, and at the same time be able to tell when they have fully deleted a file. Exposing the file table would be quite complicated to start, but there could be a tab that just shows you what files are still ‘recoverable’, similar to the standard and advanced tabs of the task manager on windows.
2. Compare the advantages of deleting information with information permanence.
   • Deleting information is vital, as the case study mentions, to ensure we all have control over our data. It allows for us to erase our mistakes, test things, and have more freedom as we use our devices, knowing we can remove things as we want. Imagine if you couldn’t rip up or shred any documents, and instead just had to keep them all in boxes around your house. Besides the clutter around the house, you would be worried about all of your private, personal, and sometimes vulnerable information being constantly there. Being unable to delete your data means every sensitive document you ever made is available for someone to hack in and see, and you can never fully prevent it. On the other hand, information permanence does remove the worry of accidentally deleting important files, and it means you can undo any modification to files you don’t like, preventing any full loss of work. This also allows law enforcement agencies to find out more info on criminals, and prevents them from fully deleting criminal records. That being said, as the case study mentioned, this will then be used by governments to spy on and exploit their populous.
3. For cryptographic erasure of a digital photograph to be truly complete, the image would need to be encrypted the moment it was taken and be decryptable by approved tools. Is there a way for such images to be edited, cropped, touched up, and incorporated into electronic publications like websites? If such a system could be designed, what would be the barriers to having it deployed?
   • Editing an image works with encryption. You can simply approve the tools to decrypt the image, and you can edit it. Once we get to uploading the images to publications, we get into more problems. To be able to have the image accessible to everyone, you need it to be unencrypted. On top of that, it would be realistically impossible to protect the images from people screenshotting them, and saving them locally. Just look at what Netflix or other DRMed services are doing to try to stop that - they are making every screenshot or recording black when their services are playing media. But even still, we have many many other ways of copying this media, and realistically there is no way to prevent all of them. Thus, local and personal encryption of your data is certainly doable, but once we get to trying to selectively publish the media online, it becomes unrealistic quite quickly.
4. Object overwriting is a straightforward, well-understood approach for eliminating the ability to recover deleted data. However, software engineers have not made object overwriting mandatory on today’s computer systems because it would negatively impact performance and battery life. This is a decision that must be made at the system level; it cannot be made a user option. Do you think that systems should employ object overwriting, or do you think that the current approach of not overwriting is correct?

   • At this point, our computers are really efficient and our drives are faster than they have ever been. The combination of these means that erasure by overwriting is the easiest it has ever been for our computers to do. I think at this point, the overhead imposed on the computer by object overwriting is somewhat minimal and the gain is worth it to have permanently deleted files. If users could have the option, a power management setting could be created that disables object overwriting when the laptop is off the charger, and then when it is plugged in, the computer will retroactively overwrite the user’s data that had been deleted. This would mitigate the power issues that come up with overwriting info, but also makes it so that we still have permanent deletions.

     My Question:

     What types of deletion do your devices do? How hard is it to figure it out?

Why?

Since currently there is very little information regarding what policies our individual devices use, I think it is a good thought exercise to try and figure it out for yourself. This will hopefully allow us to figure out what our files are doing, at the same time as helping us figure out where it would make sense to proviide information to the user about where the deletion type SHOULD be listed, since that is where we would look first.

Reflection:

This was an interesting case study. I have read and learned about these places that recover your files, but never thought to ask much about how they work, or what different file systems would make it easier to do so. This is an important topic, especially as we put more and more info on the internet and our devices, and I appreciated the opportunity to learn more about this.