1993-05-19 - Mixing ciphertext and plaintext

Header Data

From: meyer <wixer!wixer.bga.com!meyer@cactus.org>
To: cypherpunks@toad.com
Message Hash: 8804b3853cb9c2b47f3e5aa240fd536f1721751b3f6f306fd8bc2a23b21dd2b5
Message ID: <9305182056.AA12121@wixer>
Reply To: N/A
UTC Datetime: 1993-05-19 02:46:55 UTC
Raw Date: Tue, 18 May 93 19:46:55 PDT

Raw message

From: meyer <wixer!wixer.bga.com!meyer@cactus.org>
Date: Tue, 18 May 93 19:46:55 PDT
To: cypherpunks@toad.com
Subject: Mixing ciphertext and plaintext
Message-ID: <9305182056.AA12121@wixer>
MIME-Version: 1.0
Content-Type: text/plain



>Return-Path: <mdiehl@triton.unm.edu>
>Subject: mixed plaintext and crypted text.
>Date: Sat, 15 May 93 1:26:55 MDT
>
>Hey again, all. I've RTFM'd, and I don't even know if it can be done, but
>does anyone know how I can have pgp display the un-encrypted AND the
>decrypted parts of a message?  Lets say my message goes like this:
>
>This is a plaintext message to tell you stuff that needs not be private.
>BTW, can you find the subliminal message? ;^)j
>-------- begin pgp block -----
>asdfkasjd;fThEjsflajslfjaslfjadfajs;flasjdaslfjasldfjalsj
>asjlgfiuituqoNsAj;slkjasdifuoejrqlwfiasuokjel;rqwiuasdsii
>asdfasljdflasjfdSuXsldfjalsjljeqljerwljrlejqlwjerlqwjerlq
>elqrkjlasjl
>134as
>-------- end pgp block -------
>
>Thanx a lot
>
>Yours virtually,
>+-----------------------+-----------------------------+---------+
>| J. Michael Diehl ;-)  | I thought I was wrong once. | PGP KEY |
>|                       |    But, I was mistaken.     |available|

If you wish to mix plaintext and ciphertext in an email message then
you can use Dolphin Encrypt.  Let's say your message is to consist of
P1/C2/P3, plaintext/ciphertext/plaintext, where C2 is ciphertext
derived from plaintext P2.  What you do is put P2 into a file F.TXT,
then run Dolphin Encrypt with a command such as:

                       DE E F.TXT F.ENC /t

After you give Dolphin Encrypt the encryption key F.ENC will be a file
which consists of pseudo-uuencoded ciphertext (that's what the "/t" is
for).  Run your mailer program.  Write your P1.  ASCII-upload F.ENC,
which is your C2.  (No need to mark the beginning/end of the
ciphertext block.)  Finish off with your P3 and send your message.

The recipient captures the entire message as, say, G.ENC, then runs:

                       DE D G.ENC G.DEC /t

(Of course, she has to know the encryption key.)  Dolphin Encrypt
skips over P1 to get at C2 and writes G.DEC containing P2.  Voila!

For further info send me a snailmail address.

-- Peter Meyer






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