VMs: Re: Another VMS idea?

["Jeff" <jeff@xxxxxxxxxxxxxxxxxxxxxx>]

Larry Roux lroux@xxxxxxx Wrote
On 11 April 2004 14:43


> What if the author put the message in with the letters spaced and then
filled in the spaces with some sentence: ie:
>
>    T   H  I     S   I   S   A    T     E      S     T
> FRO GS  AR E FRO  GS ARE  FR OGS  AR EF ROG SA RE FR OGS ARE
>
> FROTGS HARIE FROS GSIARES FRAOGS TAR EREROG SASRE FRTOGS ARE
>
> While the above isn't quite viable, this would retain a logical letter
distribution curve (as all the characters are from a language) and may
explain repeated words.
>
> You could have multiple sentences - ie "initial P means use "JACK IS A
DULL BOY" and initial "T" is use "MARY MARY QUITE CONTRARY".
>
> This would be a "simple substitution cipher" with an easy twist and
wouldn't require the VMS to use 18th century methodology.
>
> How could you tell is something like this is being done?
>

The first step is to scan for a repeated pattern for paragraphs that start
with either P or T. The pattern would have to be consistent. So first take
every second character and try a match on that. Then every third character.
As long as you can determine what a character is. Next create a tree for T &
P paragraphs separately where a path is built for all possible combinations.
This path can be scanned for branches that occur more frequently than
others. Once the most popular branches are detected selective branches are
analysed and the equivalent letters removed from the transcription. Then the
scan is run again to see if most popular branches start to link up. If a
chain of branches then have the same popularity, hey presto you have an
inserted string.

Hope this helps.

Jeff

P.S. And no I won't be programming it I have enough to do.

______________________________________________________________________
To unsubscribe, send mail to majordomo@xxxxxxxxxxx with a body saying:
unsubscribe vms-list