Dana Kirkbride

My framing is that sharing a file shares everything the file contains, and the parts nobody put there deliberately are the ones that get missed. Documents carry properties set by the application that made them: author, last modified by, revision count, editing time, and the template it came from. Those name people.

Several office formats also keep a revision history containing text that was deleted from the visible document, which is the version most likely to contain something embarrassing. Spreadsheets carry more than people expect, including the path of the folder the file was created in, which is a shareable detail about an organisation's internal layout. Images carry the block covered in the image section, and text files carry almost nothing by design, which is a reason to prefer them when the content permits.

Embedded content is the case worth calling out. A file containing an attached document carries that document's metadata too, and stripping the outer file does not touch the inner one.

What survives a strip is worth knowing as well: a screenshot of text has no metadata because it is an image, and the same information in a flat file has none either, so the safest thing to share was never the original document. I keep every tool here running on your own device, because a file uploaded to a stripping service has been sent to that service, which is the opposite of the intent. A short check before sending is cheaper than finding out afterwards: open the file, look at its properties, and see what is still there.