Secure File Deletion - Other places files are lurking

[Ink]

HTG writes "Why Secure File Deletion Tools Aren't Foolproof" - Read more

Such tools do work on magnetic hard drives, erasing the current file’s data from the disk completely so it can’t be recovered from that place. However, there are other places that bits of the file may be lurking:

• Other Copies of the File: If, at any point, you had an additional copy of the file on your hard drive, the file may still be on your hard drive. Even if you deleted the additional copy, the deleted copy’s data may still be present on your disk.
• Temporary Files: If any program was using the file, its data may be stored in temporary files. For example, extracting a ZIP, RAR, or other archive file will often place a copy of the archive’s contents into temporary files.
• Search Indexes: Bits of the file may be recoverable from search indexes. For example, the text of a document may be present in a search index.
• Shadow Copies: Windows automatically adds copies of files to “shadow copies,” and they can be recovered using System Restore. On Windows 8, File History is constantly making backup copies and may have a backup of your files.
• Prefetch: The Prefetcher in Windows helps applications load faster by creating prefetch files for applications. If you need to securely delete an .exe file, portions of it may still be present in the Windows prefetch directory.
• Image Thumbnails: Most operating systems create thumbnail-sized copies of images so they can quickly present image thumbnails later. If you have a sensitive photo you wish to securely delete, a smaller version of that photo may still be available in a thumbnail cache.

Worse yet, if you had any of these at any point — let’s say you had an image thumbnail but deleted it — the deleted files may be recoverable. It’s very difficult to know for sure whether any data from a “securely deleted” file is actually still present on your hard drive.

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To add to the above, if you have stored or sync'd your files in-the-cloud, or across multiple trusted computer, tablets, smartphone devices.