encrypting

[Lennart Sorensen]

On Sat, Jan 17, 2004 at 01:08:23PM -0500, Michael Murray wrote:
> Actually, you could whip up a quick expect script to even automate this part
> if you really wanted to (although the security of that is obviously
> non-existant).

Then there would be no point wiping the plain text file would there? :)

> Good point.  The author points that out... I just hadn't read far enough
> when I hit the send button.
> 
> This has me thinking: shouldn't it be possible to do a byte-by-byte
> overwrite of the file in place?  Or am I misunderstanding the way that the
> journal works... Will the journal reallocate blocks that are currently
> allocated to a file?
> 
> Just thinking out loud, and showing my ignorance on the way JFSes work...

Reiserfs 3.x will overwrite files in place (this is why reiserfs is able
to get very messy file corruption with a partially rewritten file when
the system looses power, even though the meta data is completely
intact).  Fully journalled filesystems (ext3 can be, xfs is, jfs is),
will not touch existing file data until all new data is fully commited
to disk in unused blocks.  They do allocate and copy old blocks rather
than allow overwrites.

Lennart Sorensen
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