Re: [office] OFFICE-2656: Default Signing After Encryption isUnacceptable

[Thorsten Behrens <tbehrens@novell.com>]

Malte Timmermann wrote:
> I fully agree that there are valid use cases that the signature of an
> encrypted document MAY also be encrypted.
> 
> But you also should agree that there are valid use cases to not encrypt
> the signature, because you then can't verify document integrity in
> automated processes w/o knowing the encryption keys.
> 
Hi Malte,

well I guess it's really the other way 'round. Honestly, the
overwhelmingly standard case is to sign first, then encrypt
(RFC1991, 2440, etc etc). Simply put, encryption means protecting
document content from plain sight. A signature is part of the
document, and usually conveys at least some amount of likely private
information, so the default really should be to encrypt that, too.

Apart from that, all the nice things from DSIG like only signing node
sets really only work with access to the unencrypted xml streams -
so I truly feel that signing encrypted documents is the special
case, and signing first the norm, with a wealth of useful variations
suddenly then getting straight-forward, instead of being a hard
problem.

Signing first really is sine qua non - everything else is optional.

Cheers,

-- Thorsten

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