I ask because if a file is sent to someone, the file may contain personal information from other files in the top and tail ends ("slack").
Admittedly it was in the early 1990s, but when a friend first told me about this risk, I looked at a few files (with Norton Utilities I believe), and to my horror, one file had all my credit card details in at the very end of the file (after it had "officially" finished), and another contained references to lifelong medical conditions I have.
Strangely, no one seems to be bothered by (or know about?) this risk nowadays.
There is of course a host of other information, e.g., personal addresses, medical ailments, etc., that can be relayed in this manner, without the sender ever knowing.
There is an informative article on
https://whatis.techtarget.com/definition/slack-space-file-slack-space (the 3rd para. confirms what I am saying)
Alabalcho says "If you want to (eg) zero out that space, that's completely different question, but I see no practical use of this either", but surely if it has important/personal data, that is a good enough reason?
So, can anyone suggest a (freeware) program that shows the slack ends of a file and can provide the means of blanking this out?
Thanks.