Cryptography Reference
In-Depth Information
but the structure of the grammars can still affect the outcome.
A deeper exploration of
the security can be
found in Section 7.3.4.
The process of contraction can add even more confusion to the
mixture. Here's the grammar from Table 7.3.3 after several contrac-
tions:
noun
→
Bob and Ray
verb2
Fred and Barney
verb4
Laverne and Shirley
verb
Thelma and Louise
verb3
who
went fishing
where
Bob and Ray went shooting
where
Thelma and Louise went bungee-jumping
where
Fred and Barney went shooting in Minnesota.
Fred and Barney went shooting in Timbuktu.
Fred and Barney
verb5
who
→
Bob and Ray
Thelma and Louise
verb
→
went fishing
where
went shooting
where
went flying
where
went bungee-jumping in Minnesota.
went bungee-jumping in Kalamazoo.
went bungee-jumping
where2
verb2
→
went bungee-jumping
where
went flying
where
verb3
→
went shooting
where
went flying
where
verb4
→
went fishing
where
went flying
where
went bungee-jumping
where
verb5
→
went shooting in Katmandu.
went shooting in Kalamazoo.
where
→
in Minnesota.
in Timbuktu.
in Katmandu.
in Kalamazoo.
where2
→
in Timbuktu.
in Katmandu.
Two new var i ab l es ,
verb5
and
where2
, have been introduced
through a contraction. They will significantly change the relation-
ship between the bits and the choice made for several sentences. Fig-
ure 7.6 shows newHuffman trees that are used to convert bits into the
choice of productions for variables. Here's a table that shows some
sentences and the bits that produced them before and after the con-
tractions:
