[Cryptography] Steganography and bringing encryption to a piece of paper

[Jonathan Thornburg]

On Fri, Jul 18, 2014 at 10:41:26AM -0700, Bear wrote:
> Let's imagine that there is a person who is a conlang hobbyist 
> and has a diary which he keeps in an entirely made-up language.  
> It has grammar that doesn't (much) resemble the grammar of English, 
> its own vocabulary most words of which are not direct substitutions 
> for English words and are ambiguous in different ways, its own
> morphology (derived from three earlier made-up languages) and 
> system of affixes and infixes, and its own set of a few thousand 
> made-up idiomatic phrases.  Some of these made-up idioms are 
> "linguistic fossils" from earlier made-up languages, which don't 
> make sense according to the rules of the current language's grammar.
> 
> Its only relation to words in existing languages are via proper 
> nouns, which are handled via a sequence of syllable substitution 
> and sound-change rules that result in pronounceable but apparently
> unrelated strings that are (usually) longer or (sometimes) shorter 
> and otherwise conform to the lexicographic conventions of his 
> made-up language.  
> 
> Further, the transformation rules are not reversible; while there 
> may be only one 'image' in the constructed language for a given 
> proper noun, the constructed word could be the result of applying 
> the process to any of billions of possible preimage strings - of 
> which possibly only one or possibly as many as a few dozen are 
> genuinely proper nouns from which it might have been derived.  And, 
> to make matters worse than that, almost every *other* word in the
> language could also result from the same set of substitution rules, 
> each with billions of possible preimages which might include zero,
> one, or as many as a few dozen completely unrelated proper nouns.
[[...]]
> 
> While not "encrypted" as such, I doubt that anyone who got their 
> hands on his journal could, in any reasonable timeframe or possibly
> ever, read it.  With no illustrations or passages in English to 
> relate to the written words, the proper nouns are the only 
> relationship it has to the real world, and that relationship is 
> itself tenuous. To those who had not spent time learning the 
> language from someone who, ultimately, learned it from the guy 
> who made it up, it should be  as impenetrable as the Voynich
> manuscript.

Alternatively, as impenetrable as
  130 13042 13401 8501 115 3528 416 17214 6491 11310
  18147 18222 21560 10247 11518 23677 13805 3494 14936
  ...
(the first two lines of the Zimmermann Telegram,
http://en.wikipedia.org/wiki/Zimmerman_Telegram).

The Zimmerman-telgram code had a many-to-one mapping from German words
to codewords, large numbers of nulls, and various other measures to
confuse any attempted decryption.  But Room 40 still broke it.

A rereading of Kahn "The Codebreakers" on the era of Nomenclatures and
beyond does not offer high hopes of this diary-code staying unbroken if
the NSA decides it's worth a few analyst-months and GPU-centuries...

ciao,

-- 
-- "Jonathan Thornburg [remove -animal to reply]" <jthorn at astro.indiana-zebra.edu>
   Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
   currently on the west coast of Canada
   "There was of course no way of knowing whether you were being watched
    at any given moment.  How often, or on what system, the Thought Police
    plugged in on any individual wire was guesswork.  It was even conceivable
    that they watched everybody all the time."  -- George Orwell, "1984"