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Re: secure sign & encrypt

2002-05-23 08:04:56

Hash: RIPEMD160

vedaal wrote:
----- Original Message -----
From: "Terje Braaten" <Terje(_dot_)Braaten(_at_)concept(_dot_)fr>
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:

Disastry <----PGP plugins for Netscape and MDaemon
 ^----PGP 2.6.3ia-multi06 (supports IDEA, CAST5, BLOWFISH, TWOFISH,
      AES, 3DES ciphers and MD5, SHA1, RIPEMD160, SHA2 hashes)
Version: Netscape PGP half-Plugin 0.15 by Disastry / PGPsdk v1.7.1


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