Re: safety of encrypted filesystems
On Fri, 17 Jun 2005 08:46:03 +0200
martin f krafft <madduck@debian.org> wrote:
> Of course blocks are small, e.g. 64 bytes. However, doesn't CBC or
> EBC make sure that every block is chained to its predecessor, making
> even the very last block of a file dependent on the bits of the very
> first block?
No.
If it would be that way, it would allways be necessary to decrypt the
whole filesystem, when you want to read the last block. Or you have to
store a decrypted version in memory...
And also, when you write any block, you have to reencrypt all the
remaining blocks.
I don't know, what kind of CPU you use, but on my system, that would be
really time consuming!!!
The loss of a single block on a harddist "should" be protected by using
some kind of "forward error correction" like the Solomon-Reed one.
--
mit freundlichen Gruessen / with friendly regards
Michael Buchholz
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