I think you are agreeing with me. I'm certainly am agreeing with you.
Let me know if you disagree,
-Rob
"Dennis E. Hamilton" <> wrote on 05/12/2010
12:20:11 PM:
>
> RE: [office] Encryption and data leakage
>
> Rob, I'm not sure I understand which approach these last concerns are
about.
> (I see there are now later notes in this exchange while I was writing
this,
> so I may be even more out of sync than I think already.)
>
> 1. It strikes me that it is easier to make a Zip, encrypt the whole
thing,
> and then include it in a Zip along with a manifest and a file that
provides
> the encryption parameters than almost anything else. This should work
with
> standard Zip-handling libraries. In the OpenDocument case, since
whatever
> producer is doing this already knows how to make an ODF Package, it
> certainly can make the outer wrapper using the same machinery. One can
also
> avoid compression of the inner, encrypted payload Zip, so I suspect this
can
> be done in a single pass on top of the unencrypted save of the payload
Zip.
>
> 2. I don't think the act of full-document encryption is technically
> difficult. With regard to the encryption-descriptor, using a profile of
XML
> Encryption strikes me as the ideal case, it being extremely valuable to
rely
> on existing work in this situation. That is probably the biggest impact
on
> implementers, but the benefit is also quite high. And since products
that
> do XML DSig must already deal with certification stores, that aspect is
> already in hand and gives us even more consistency and reliance on
existing
> technology. There are likely some known libraries and more-widely
available
> material on threat models against the encrypting application as well.
>
> 3. But there may be use-case issues and only implementers of
OpenDocument
> products can say what those specific issues are. For example, ODFDOM
would
> perhaps need to adjust its model to support this and have it work at the
> right point in time. More seriously, tying encryption to Save As ...
(as
> now done in OO.o) would be problematic, and it would appear that signing
and
> encryption would both need to be operations on [being-]saved documents
(just
> like, for e-mail, the cases are selected in advance, even as defaults,
but
> it is the send[-to-outbox] that carries out the actions and requests any
> Pass Phrases that are required for private keys to be accessed and
> certificates to be applied, etc.
>
> Or were you addressing a different one of the options under discussion?
> Bob was commenting about possible IP issues using PKware's proprietary
> encryption and DSig arrangements. I would avoid those simply to use a
> widely-recognized standard mechanism (e.g., XML Encryption and XML DSig
plus
> XadES, etc.) as much as possible.
>
> - Dennis
>
> (Side note: The e-mail software I use allows signing and/or encryption,
with
> no indication as to sequence. I am confident that signing applies to
the
> unencrypted content, including attachments.)
>
> - - - - - - - - - - - - -
> Standards are arbitrary solutions to recurring problems (R. W. Bemer)
> Although not by becoming the recurring problem (orcmid).
> When you find yourself in a hole, stop digging.
>
>
>
> -----Original Message-----
> From: [mailto:]
> <http://lists.oasis-open.org/archives/office/201005/msg00268.html>
> Sent: Wednesday, May 12, 2010 06:01
> To: Bob Jolliffe
> Cc: Malte Timmermann;
> Subject: Re: [office] Encryption and data leakage
>
> I'd also be concerned about library support for that form of encryption.
> Specifically, if you have a ZIP library in your platform or language
> libraries, but it does not support ZIP encryption, it will be far easier
> to code a pre-ZIP encryption method than to modify the way your system
> library handles ZIPs.
>
> -Rob
>
>
> Bob Jolliffe <> wrote on 05/12/2010 05:22:08 AM:
> <http://lists.oasis-open.org/archives/office/201005/msg00261.html>
> [ ... ]
>
