"Joel Garry" <joel-garry_at_home.com> wrote in message
news:91884734.0405101645.593c11d9_at_posting.google.com...
> sandell_at_pacbell.net (Bruce) wrote in message
news:<595024a5.0405061514.5f256b15_at_posting.google.com>...
> > I have a table with some sensitive customer data in it. I am now
> > keeping all the data in another table, and encrypting it. I want to
> > get rid of the original unencrypted data and be sure that it is no
> > longer anywhere on disk. Should I drop the table, or first delete the
> > rows and then clear the redo logs? I'm not sure how to know if the
> > data is actually physically deleted from disk, or if it's still there,
> > but just in blocks that get marked as available. Any guidance would
> > be greatly appreciated.
> >
> > Thanks,
> > Bruce
>
> I composed a great answer to this on Friday, but google lost it, silly
> me I was cutting and pasting from an x-window before things scrolled
> off and didn't copy the google window before hitting the post button.
> Anyways, it demonstrated that you can grep the datafiles for
> particular data after deleting rows.
>
> So the answer is, you must write over all rows before deleting, since
> you never know when oracle is going to deign to re-use the segments,
> and you must switch logfiles more than once to actually get the
> rewrites to disk.
>
> Then you must burn all your backup tapes.
And all your filing cabinets.
--
Niall Litchfield
Oracle DBA
Audit Commission UK
http://www.niall.litchfield.dial.pipex.com/
Received on Tue May 11 2004 - 03:29:46 CDT
