> will overwrite individual files multiple times
>I've read that these tools typically write zeros on top of the files five times or so
Laboratory tests carried out by people who are
very serious about this sort of thing (for example the NSA, and the CMRR) have demonstrated that multiple overwrites are no more secure than a single overwrite on drives released in the last decade
>SDelete
SDelete dates from 1999, the era when you could still just about recover data that has been only overwritten once and, as such, implements the then active DOD 5220.22-M (indeed, they proudly mention this on the web page). That document has been obsolete for some years now, and is replaced by
NIST 800-88 which a) no longer stipulates multiple overwrites to delete data securely and b) officially makes the point that I've made above - single overwrites are as effective as multiple overwrites these days
(BTW, this isn't to say SDelete is not a good tool; it's just you can happily operate it in single-pass mode and safe yourself a bunch of time ...)
Just to be clear - I'm not suggesting that simple overwriting of data (single or multiple pass) using a 3rd party tool will defeat laboratory attack, just that multiple write are no more effective than single writes, and that tools that proudly proclaim that they implement DOD 5220 (as many do) are living in the past.
Having said that ...
>and wiping wouldn't be enough
Actually, modern (S)ATA drives (anything built from 2001 onwards) come with a built-in single-pass wipe command (Secure Erase) that will render data unrecoverable even by laboratory attack methods.
The CMRR provide a tool to invoke this command
here
