Re: VMs: Three frequency tables

["Jeff" <jeff@xxxxxxxxxxxxxxxxxxxxxx>]

Nick Pelling incoming@xxxxxxxxxxxxxxxxx
20 December 2003 17:08
Subject: Re: VMs: Three frequency tables


> Hi Jeff,
>
> At 16:38 20/12/2003 +0000, Jeff wrote:
> >Dennis tsalagi@xxxxxxxx wrote
> > > But what else are you thinking of?  Do you mean that
> > > you don't think the gallows are just markers for cipher
> > > change?  (I've never liked that either, but that
> > > because it doesn't look like a polyalphabetic cipher to
> > > me.)
> >
> >The VMS is a polymorphic alphabetic cipher. There is a difference.
>
> What is a "polymorphic alphabetic cipher"? What is the difference between
> one of those and a polyalphabetic cipher?
>
> Cheers, .....Nick Pelling.....
>

The polymorphic cipher will not give a letter for letter substitution. Like
a polyalphabetic. However single substitution is not used. An example.

Take a line from the VMS.

shoy.ckhey.kodaiin.cphy.cphodaiils.cthey.she.oldain.d

We need to analyse this with all spaces removed. The analysis will look for
triplets of EVA characters. It could also be applied to a text with cth etc
substituted with single letters if that is your preference. You then get a
table of occurance counts part of which is shown below.

cho - 522
iin - 376
aii - 357
dai - 255
hol - 253
hor - 234
chy - 231
cth - 208
sho - 186
tch - 163
kch - 162
che - 148
hod - 98
otc - 95
cha - 86

The numbers indicate how many times the triplet occurs, both within VMS
words and across word boundaries. When we begin to plot letters for these
individual triplets we can start to place conconant and vowel positions.
Here is the same part of the table partially filled in.

cho - 522 e
iin - 376 e
aii - 357 l
dai - 255 l
hol - 253 l
hor - 234 r
chy - 231 o
cth - 208 i
sho - 186 e
tch - 163 n
kch - 162 c
che - 148 c
hod - 98  r
otc - 95  e
cha - 86

Here is the same line above using the full table with assumed substitutions.
Where each identified triplet stands for one letter.

__e_.__cci.lacalle.dico.decarallio.__ici.__e.istale.n
shoy.ckhey.kodaiin.cphy.cphodaiils.cthey.she.oldain.d

Note the "phrase" la calle dico de carralio. Letters always resolve into set
positions with this method. If you already have the pattern d_c_ it will
usually place an i between the d & c and an o after the c. The VMS patterns
do this automatically and cannot be influenced by changes to the method.
Syllable formation just happens automatically. Unlike my previous attempts
with pairified ciphers, illegal multiple vowel and consonant groups just
don't form.

Each triplet final glyph position will stand for a single substitution
letter for that triplet only. So an h at the end of kch will produce a
different letter than the h at the end of cth. Hence polymorphic. The
pattern changes with varied pathways through the table. This is the
information I sent to Jacques Guy that he used for his own cipher and which
produced the interesting entropy values.

If his tests on Latin, German and Greek differ in any way from his English
tests then that will be very interesting.

NOTE A high percentage of triplets occur with below 20 occurances and could
be links to realign word ending patterns to maintain the repetative
structure. The entropy match alone seems significant. However I am now
finding a divergence from Italian using some new tests. This could arise
from the forced structure imposed on the text. This would disrupt any
attempt to do language pattern matching.

My next step is to analyse triplet distances, where I select two distinct
triplets and measure average distance between them on lines where they both
occur. If these numbers are consistent then I can assume syntactical
structure and not simply random mechanical construction.

Again all comments welcome.

Jeff


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