<s>
In	O
cryptography	O
,	O
NewDES	B-Algorithm
is	O
a	O
symmetric	B-Algorithm
key	I-Algorithm
block	O
cipher	O
.	O
</s>
<s>
It	O
was	O
created	O
in	O
1984	O
–	O
1985	O
by	O
Robert	O
Scott	O
as	O
a	O
potential	O
DES	B-Algorithm
replacement	O
.	O
</s>
<s>
Despite	O
its	O
name	O
,	O
it	O
is	O
not	O
derived	O
from	O
DES	B-Algorithm
and	O
has	O
quite	O
a	O
different	O
structure	O
.	O
</s>
<s>
Its	O
intended	O
niche	O
as	O
a	O
DES	B-Algorithm
replacement	O
has	O
now	O
mostly	O
been	O
filled	O
by	O
AES	B-Algorithm
.	O
</s>
<s>
The	O
algorithm	O
was	O
revised	O
with	O
a	O
modified	O
key	B-Algorithm
schedule	I-Algorithm
in	O
1996	O
to	O
counter	O
a	O
related-key	O
attack	O
;	O
this	O
version	O
is	O
sometimes	O
referred	O
to	O
as	O
NewDES-96	O
.	O
</s>
<s>
In	O
2004	O
,	O
Scott	O
posted	O
some	O
comments	O
on	O
sci.crypt	B-General_Concept
reflecting	O
on	O
the	O
motivation	O
behind	O
NewDES	B-Algorithm
's	O
design	O
and	O
what	O
he	O
might	O
have	O
done	O
differently	O
so	O
as	O
to	O
make	O
the	O
cipher	O
more	O
secure	O
.	O
</s>
<s>
NewDES	B-Algorithm
,	O
unlike	O
DES	B-Algorithm
,	O
has	O
no	O
bit-level	O
permutations	O
,	O
making	O
it	O
easy	O
to	O
implement	O
in	O
software	O
.	O
</s>
<s>
It	O
is	O
a	O
product	B-Algorithm
cipher	I-Algorithm
,	O
consisting	O
of	O
17	O
rounds	O
performed	O
on	O
a	O
64-bit	O
data	O
block	O
and	O
makes	O
use	O
of	O
a	O
120-bit	O
key	O
.	O
</s>
<s>
In	O
each	O
round	O
,	O
subkey	O
material	O
is	O
XORed	O
with	O
the	O
1-byte	O
sub-blocks	O
of	O
data	O
,	O
then	O
fed	O
through	O
an	O
S-box	B-Algorithm
,	O
the	O
output	O
of	O
which	O
is	O
then	O
XORed	O
with	O
another	O
sub-block	O
of	O
data	O
.	O
</s>
<s>
In	O
total	O
,	O
8	O
XORs	B-Application
are	O
performed	O
in	O
each	O
round	O
.	O
</s>
<s>
The	O
S-box	B-Algorithm
is	O
derived	O
from	O
the	O
United	O
States	O
Declaration	O
of	O
Independence	O
(	O
used	O
as	O
a	O
nothing-up-my-sleeve	O
number	O
)	O
.	O
</s>
<s>
Only	O
a	O
small	O
amount	O
of	O
cryptanalysis	O
has	O
been	O
published	O
on	O
NewDES	B-Algorithm
.	O
</s>
<s>
The	O
designer	O
showed	O
that	O
NewDES	B-Algorithm
exhibits	O
the	O
full	O
avalanche	O
effect	O
after	O
seven	O
rounds	O
:	O
every	O
ciphertext	O
bit	O
depends	O
on	O
every	O
plaintext	O
bit	O
and	O
key	O
bit	O
.	O
</s>
<s>
Biham	O
's	O
related-key	O
attack	O
can	O
break	O
NewDES	B-Algorithm
with	O
233	O
chosen-key	O
chosen	O
plaintexts	O
,	O
meaning	O
that	O
NewDES	B-Algorithm
is	O
not	O
as	O
secure	O
as	O
DES	B-Algorithm
.	O
</s>
<s>
John	O
Kelsey	O
,	O
Bruce	O
Schneier	O
,	O
and	O
David	O
Wagner	O
used	O
related-key	O
cryptanalysis	O
to	O
develop	O
another	O
attack	O
on	O
NewDES	B-Algorithm
;	O
it	O
requires	O
232	O
known	O
plaintexts	O
and	O
one	O
related	O
key	O
.	O
</s>
