Re: secure sign & encrypt

[[e-mail]]

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vedaal wrote:
> ----- Original Message -----
> From: "Terje Braaten" <[e-mail]>
> Sent: Monday, May 20, 2002 7:31 PM
> Subject: RE: secure sign & encrypt
> 
> [...]
> 
>  > The problem is that most users when they decrypt a message
> > that is signed, they will think they can be sure the signer
> > and the encrypter is the same person/entity.
> > It would be a major improvement in the OpenPGP specification
> > to allow applications to ensure that that really is the case.
> 
> [...]
> 
> Functionally, that is the case now in Open PGP.
> 
> Even though a signed and encrypted message can be separated into a
> verifiable free standing signed message, and then
> re-encrypted and sent on to someone else,
> it 'cannot' {afaik} be re-combined into a signed and encrypted message that
> appears the same as a de-novo signed and encrypted message.

it can be done.
it's even not necessary to fully decrypt the message,
one can just decrypt only pubkey encryption to get session key,
then encrypt this session key to other pubkey!

what bothering me more is that fake pubkey encryption packets can be added
by man in the middle so that recipient thinks that message was encrypted
to him and to other preson.

I wrote about it here:
http://lists.gnupg.org/pipermail/gnupg-devel/2001-August/006285.html

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