Hi
My friend just returned my USB. He used my USB to store his data and returned me after deleting it, thinking that his data is permanently deleted from my USB. But we know that this data can be recovered using data recovery softwares (like photorec/testdisk etc.). So, here is a question that (except shred) how to securely format/wipe my USB that I (or someone else) cannot recover his (deleted) data. shred is effective when data is already present. But after simple deletion, it can be recovered. So, how to securely erase empty space in USB?
Thanks

microwave oven for example. Or a hammer. (if reformat/shred/whatever weren't good enough).
Long time ago I read some low level formatter, I don't know if they are still available.
But first, if you want to secure your data you need to create an encrypted volume on that drive. Without key that will be useless, so you don't really need to wipe it at all.

Is there anything like 'secure wipe' or 'secure format'? Few years back I was installing Hackintosh in one of my pc and during installation, it gave an option of 'secure format/wipe'.

We call it "zeroing out".

I was just typing the same thing to ask
Is:
same like "dd if=/dev/zero of=/dev/sdX"?

Found here:
https://wiki.archlinux.org/index.php...ite_the_target

I'd imagine so. The point is to overwrite all the data on the disk, and both methods do that.

Thanks a lot.