<s>
In	O
cryptography	O
,	O
partitioning	B-General_Concept
cryptanalysis	I-General_Concept
is	O
a	O
form	O
of	O
cryptanalysis	O
for	O
block	O
ciphers	O
.	O
</s>
<s>
Harpes	O
originally	O
replaced	O
the	O
bit	O
sums	O
(	O
affine	B-Algorithm
transformations	I-Algorithm
)	O
of	O
linear	O
cryptanalysis	O
with	O
more	O
general	O
balanced	O
Boolean	O
functions	O
.	O
</s>
<s>
He	O
demonstrated	O
a	O
toy	O
cipher	O
that	O
exhibits	O
resistance	O
against	O
ordinary	O
linear	O
cryptanalysis	O
but	O
is	O
susceptible	O
to	O
this	O
sort	O
of	O
partitioning	B-General_Concept
cryptanalysis	I-General_Concept
.	O
</s>
<s>
In	O
its	O
full	O
generality	O
,	O
partitioning	B-General_Concept
cryptanalysis	I-General_Concept
works	O
by	O
dividing	O
the	O
sets	O
of	O
possible	O
plaintexts	O
and	O
ciphertexts	O
into	O
efficiently-computable	O
partitions	O
such	O
that	O
the	O
distribution	O
of	O
ciphertexts	O
is	O
significantly	O
non-uniform	O
when	O
the	O
plaintexts	O
are	O
chosen	O
uniformly	O
from	O
a	O
given	O
block	O
of	O
the	O
partition	O
.	O
</s>
<s>
Partitioning	B-General_Concept
cryptanalysis	I-General_Concept
has	O
been	O
shown	O
to	O
be	O
more	O
effective	O
than	O
linear	O
cryptanalysis	O
against	O
variants	O
of	O
DES	B-Algorithm
and	O
CRYPTON	B-Algorithm
.	O
</s>
