From: Jiri Baum <jirib@cs.monash.edu.au>
Date: Wed, 25 Oct 95 19:24:55 PDT
To: sjb@universe.digex.net (Scott Brickner)
Subject: Re: A secure cryptosystem with a 40-bit key?
In-Reply-To: <199510251650.MAA24629@universe.digex.net>
Message-ID: <199510260221.MAA29674@molly.cs.monash.edu.au>
MIME-Version: 1.0
Content-Type: text/plain


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Hello cypherpunks@toad.com
  and Scott Brickner <sjb@universe.digex.net>

S.B. writes:
> Jiri Baum writes:
> >.u'u I believe that you were wrong when you expressed a symbol for the
...
> Well, I was definitely oversimplifying things.

No problem. You just have to be careful when you are generating your
wordlist, that's all.

...
> >Yeah, and a huge beast it is. If you can make a YACCable language with
> >one page of rules (say 16 :-) ), *then* I'll be impressed.
> 
> I'm sure that one could be done on one page, but I doubt it would have
...

One would need a great deal of inspiration to make it work. However,
I do think that it is possible.

...
> >> A message written entirely using native Lojban words can be encrypted
> >> in a codebook fashion where the particular codebook to be used is a
> >...
> >You have to be careful here - the structure words (cmavo) are divided
...
> To achieve the goal of the cryptosystem it may not be necessary to
> encode the cmavo, since they have no real meaning on their own, just
...

How about the numerical cmavo? You'd want to encode numbers. And you
don't want people to know they are numbers, because they could
count the digits (to get order of magnitude). Same for spelling cmavo.

How about the tense system? You'd want to encode that because it could
give important hints to locations (and times). Then again you could
probably avoid using the "a little to the north and a long way east" tense
altogether...

How about the attitudinals?

> The selma'o that only have one member are especially meaning-free, as
> they're typically elidable terminators and such.

Like I said, I only glanced at it, but how about NAI and GAI?

...
> >Yes, but the grammatical structure itself may reveal heaps.
> >(Except for trivial statements.)
> 
> In a natural language this might be true, but in Lojban the grammar's
> regularity eliminates much of this information.
...

I'm not sure I'd agree here. I suspect you are overestimating the regularity
of lojban grammar (then again maybe I'm underestimating...).

...
> >Not really; you just need to make sure that you conjugate the coded words.
> >(Ie substitute nouns for nouns, verbs for verbs, etc.)
> 
> Irregularities make this nearly impossible for computers, though.

Yes (though I'd feel quite confident doing it for Esperanto).

> There are also problems due to ambiguity.

Yup. If it's really a problem - ambiguity in language has been with us
for a long time and nobody minds much. But I guess you wouldn't want
arbitrary ambiguity in your text (you could have an interactive coder
which immediately alerts you to all alternative meanings). Or you could
put marks into your text to separate the word parts (like some beginner
Esperanto books do) thus eliminating the problem.

> The even bigger inconvenience with natural laguages comes in defining
> the codebook.
...

I'm sure you could easily find wordlists giving the "first X" words of
Esperanto - you could just standardize on one of them.


Mi esperas ke tio cxi sencas...

Adiaux - Jiri
- --
<jirib@cs.monash.edu.au>     <jiri@melb.dialix.oz.au>     PGP 463A14D5

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