NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/comp/dcom/fax/2426

Text File | 1993-01-12 | 2.8 KB | 56 lines

Newsgroups: comp.dcom.fax
Path: sparky!uunet!pipex!doc.ic.ac.uk!cc.ic.ac.uk!imperial.ac.uk!vulture
From: [e-mail] (Thomas Sippel - Dau)
Subject: Re: Fax with encryption?
Message-ID: <[e-mail]>
Sender: [e-mail] (Thomas Sippel - Dau)
Nntp-Posting-Host: cscgc
Reply-To: [e-mail]
Organization: Imperial College of Science, Technology and Medicine
References: <[e-mail]> <[e-mail]>
Date: Tue, 12 Jan 93 13:31:57 GMT
Lines: 42

In article <[e-mail]>, [e-mail] (Mathias Koerber) writes:
- Thomas Sippel - Dau ([e-mail]) [me] wrote:
-
- : Or you can view the bitstream that represents the pixels on a sheet of
- : paper as a message, and encrypt that. This would need a configurable lookup
- : table in the receiving fax machine, and a keyword exchange mechanism,
- : presumably a public key system.
.....
- No, no. What I'm thinking of is just an extension to the existing protocol.
- Like now the faxes can negotiate whether a fax is in normal or fine mode,
- there should be bit that tells the receiving fax that the message was
- encrypted. The key does not even get passed, nor does a part of it.
- Both sides will have to agree on a key to use, which is then keyed into the
- fax-machine.
.....
Your idea is really technology driven: It works for fax modems and would
be easy to implement there, but it makes no sense on fax machines which
have their mass storage in printed rather than post-processable form.

To implement with a fax modem, you would keep the tiff-file line structure,
thus ecrypting byte blocks. And you could use just a simple XOR encrypter
to do that.

I guess you could get an OEM job done from Magic Software (creators of
MTEZ), whose fax software is often being bundled with fax modems.
You would not even need an extension to the protocol for that, as it should
be perfectly obvious that the fax is encrypted to whoever is previewing
it. Or you could try to look at faxpax or netfax and bring it up on
your machine. (N.B. not for the feint-hearted, unless you run BSD.)

But you still loose the universality, i.e. you cannot just send encrypted
fax messages to any fax number and expect the message to get through,
It would need to be a fax modem and the software would need to be
understanding encryption.

                               Thomas
--
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