<s>
Anubis	B-Algorithm
is	O
a	O
block	O
cipher	O
designed	O
by	O
Vincent	O
Rijmen	O
and	O
Paulo	O
S	O
.	O
L	O
.	O
M	O
.	O
Barreto	O
as	O
an	O
entrant	O
in	O
the	O
NESSIE	O
project	O
,	O
a	O
former	O
research	O
program	O
initiated	O
by	O
the	O
European	O
Commission	O
in	O
2000	O
for	O
the	O
identification	O
of	O
new	O
cryptographic	O
algorithms	O
.	O
</s>
<s>
Anubis	B-Algorithm
operates	O
on	O
data	O
blocks	O
of	O
128	O
bits	O
,	O
accepting	O
keys	O
of	O
length	O
32N	O
bits	O
(	O
N	O
=	O
4	O
,	O
...	O
,	O
10	O
)	O
.	O
</s>
<s>
It	O
is	O
designed	O
as	O
a	O
substitution	B-Algorithm
–	I-Algorithm
permutation	I-Algorithm
network	I-Algorithm
,	O
which	O
bears	O
large	O
similarity	O
to	O
Rijndael	B-Algorithm
.	O
</s>
<s>
Like	O
KHAZAD	B-Algorithm
,	O
designed	O
by	O
the	O
same	O
authors	O
and	O
also	O
submitted	O
to	O
NESSIE	O
,	O
it	O
uses	O
involutions	B-Algorithm
for	O
the	O
various	O
operations	O
.	O
</s>
<s>
An	O
involution	B-Algorithm
is	O
an	O
operation	O
whose	O
inverse	O
is	O
the	O
same	O
as	O
the	O
forward	O
operation	O
.	O
</s>
<s>
In	O
other	O
words	O
,	O
when	O
an	O
involution	B-Algorithm
is	O
run	O
twice	O
,	O
it	O
is	O
the	O
same	O
as	O
performing	O
no	O
operation	O
.	O
</s>
<s>
Both	O
the	O
S-box	B-Algorithm
and	O
the	O
mix	O
columns	O
operations	O
are	O
involutions	B-Algorithm
.	O
</s>
<s>
Although	O
many	O
involutional	O
components	O
can	O
make	O
a	O
cipher	O
more	O
susceptible	O
to	O
distinguishing	O
attacks	O
exploiting	O
the	O
cycle	O
structure	O
of	O
permutations	B-Algorithm
within	O
the	O
cipher	O
,	O
no	O
attack	O
strategy	O
for	O
the	O
Anubis	B-Algorithm
cipher	O
has	O
been	O
presented	O
.	O
</s>
<s>
There	O
are	O
two	O
versions	O
of	O
the	O
Anubis	B-Algorithm
cipher	O
;	O
the	O
original	O
implementation	O
uses	O
a	O
pseudo-random	O
S-box	B-Algorithm
.	O
</s>
<s>
Subsequently	O
,	O
the	O
S-box	B-Algorithm
was	O
modified	O
to	O
be	O
more	O
efficient	O
to	O
implement	O
in	O
hardware	O
;	O
the	O
newer	O
version	O
of	O
Anubis	B-Algorithm
is	O
called	O
the	O
"	O
tweaked	O
"	O
version	O
.	O
</s>
<s>
The	O
authors	O
claim	O
the	O
algorithm	O
to	O
be	O
secure	O
against	O
a	O
number	O
of	O
attacks	O
,	O
including	O
four-round	O
differential	O
and	O
linear	O
analysis	O
,	O
as	O
well	O
as	O
related-key	O
,	O
interpolation	O
,	O
boomerang	O
,	O
truncated	B-General_Concept
differential	I-General_Concept
,	O
impossible	O
differential	O
,	O
and	O
saturation	O
attacks	O
.	O
</s>
<s>
Nonetheless	O
,	O
because	O
of	O
the	O
cipher	O
's	O
similarity	O
with	O
Rijndael	B-Algorithm
it	O
was	O
not	O
considered	O
to	O
offer	O
any	O
convincing	O
advantages	O
and	O
thus	O
was	O
not	O
included	O
in	O
the	O
second	O
evaluation	O
phase	O
of	O
the	O
NESSIE	O
project	O
.	O
</s>
<s>
Anubis	B-Algorithm
is	O
named	O
after	O
the	O
Egyptian	B-Algorithm
god	I-Algorithm
of	O
entombing	O
and	O
embalming	O
,	O
which	O
the	O
designers	O
interpreted	O
to	O
include	O
encryption	O
.	O
</s>
