re: separation of signed and encrypted messages

["vedaal" <[e-mail]>]

David Hopwood wrote:

>vedaal wrote:
> is there any way to separate a message that was signed and encrypted
> to a dh key, into a free-standing verifiable signed message?

>If-and-only-if the private encryption key is known, yes. This is no
>different to 'sign and RSA-encrypt'

yes,
but is there any way to do it, short of rewriting gpg, pgp to include a -d
command similar to the -d command of 2.6.3?

on a related note:

the separation that can be done now, is from 2.6.x using the command:
  pgp -da (filename).pgp
which (after giving the correct passphrase), produces
 filename.asc
which is a free-standing armored signed file, verifiable, and displaying the
text of the original message,
but,
is clearly different from an intentional armored signature file, which
usually begins with 'ow' as the first two characters
of the pgp block,

so,

would it be possible to somehow link such a separated signed file, and show
that it had to be from a specific
signed and encrypted file?  {possibly through an mdc tag on the armor}

if it 'could' be done,

then, one would 'not' have to surrender a session key or secret key, to
decrypt a signed and encrypted e-mail,

one could simply {from a remote area, without anyone needed to 'witness' the
decryption process}
separate it into the armored signed file, and release that to the
'authorities', and show that it had to have come from
the specific signed and encrypted e-mail in question.


vedaal