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From: David Entwistle <qnivq.ragjvfgyr@ogvagrearg.pbz>
Newsgroups: sci.crypt
Subject: Re: @ SCOS Message Format ?
Date: Sun, 23 Feb 2025 10:19:37 -0000 (UTC)
Organization: A noiseless patient Spider
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On Sat, 22 Feb 2025 08:57:02 +0000, Richard Heathfield wrote:

> Assumes "facts" not in evidence.

Quite right to ask. :)

You are probably correct in a lot of what you say, and I accept I may be 
wrong in much of what I say. Particularly emulation, maybe that isn't the 
cause of my problem.

I've posted some test sequences of the SCOS character set to uk.telecom. 
Feel free to have a look using your preferred reader. I've concentrated on 
the sequences where I've noticed I have a problem. There may be others I 
haven't thought about. They set off as a tidy column of numbers, letters 
and punctuation marks that are taken from the SCOS character set. I have 
included back tick, for completeness.

I've then read the posts using Pan and Thunderbird. Both exhibit some 
issues which would prohibit successful decryption in certain 
circumstances. 

Some of the sequence of characters that could be interpreted as emoticons 
get removed and are replaced by unicode characters (or something else) and 
displayed as an emoticon in both readers. In both cases the underlying 
characters never reach the reader's display, so any attempt at 
decrytption, using the ciphertext as presented, will fail. This includes:

:) – Smiley face
:( – Sad face
;) – Wink
:'( – Crying

The use of char(94) breaks the line feed in Pan's display window. Not a 
huge problem, but just a p.i.t.a.
The use of char(42) causes text to be in bold in Pan's display window. 
Again not a big problem.

I could work through the somewhat mangled ciphertext I see and replace the 
unicode characters with the original ASCII ones, but that isn't going to 
be a particularly easy learning experience for someone new to 
cryptography. Coupled with the other formatting issues make it feel a bit 
of a uphill task, which is easy to avoid if we accept some restriction on 
the character set.

Please don't feel I getting at you over this. I'd like to take a greater 
part in sci.crypt, but I don't think we're all seeing the same things, 
which makes participation difficult.

Best wishes,

-- 
David Entwistle