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

[Bear]

On Fri, 2014-07-18 at 09:08 +0200, Grégory Alvarez wrote:

> Steganography has been around for a long time but the problem with
> these techniques is that they are easily defeated. The objective with
> Steno.io is to bring the robustness of an electronic encryption
> algorithm to paper. 

Okay, I have a hypothetical.  Let's call it the "Voynich 
alternative."  Redirecting intellectual effort from cryptography
as such to linguistics could plausibly result in an arguably 
practical system of storing handwritten information privately.  
It would be a system of limited utility at best because you'd 
have to actually spend up to a year or two internalizing the 
system in your own squishy brain before it would be usable to
you, or your correspondent.  

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.

As a conlang weirdo, he's fluent in his constructed language.  But 
he's the only person who has ever used it, and has not published it 
anywhere.  It represents a monumental amount of very much enjoyed 
but arguably wasted intellectual effort on his part, in much the 
same way that Tolkien's middle-earth languages did prior to the
publication of his books.  

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.