<s>
In	O
cryptography	O
,	O
KHAZAD	B-Algorithm
is	O
a	O
block	O
cipher	B-Application
designed	O
by	O
Paulo	O
S	O
.	O
L	O
.	O
M	O
.	O
Barreto	O
together	O
with	O
Vincent	O
Rijmen	O
,	O
one	O
of	O
the	O
designers	O
of	O
the	O
Advanced	B-Algorithm
Encryption	I-Algorithm
Standard	I-Algorithm
(	O
Rijndael	B-Algorithm
)	O
.	O
</s>
<s>
KHAZAD	B-Algorithm
is	O
named	O
after	O
Khazad-dûm	O
,	O
the	O
fictional	O
dwarven	O
realm	O
in	O
the	O
writings	O
of	O
J	O
.	O
R	O
.	O
R	O
.	O
Tolkien	O
(	O
see	O
also	O
Khazad	B-Algorithm
)	O
.	O
</s>
<s>
KHAZAD	B-Algorithm
was	O
presented	O
at	O
the	O
first	O
NESSIE	O
workshop	O
in	O
2000	O
,	O
and	O
,	O
after	O
some	O
small	O
changes	O
,	O
was	O
selected	O
as	O
a	O
finalist	O
in	O
the	O
project	O
.	O
</s>
<s>
KHAZAD	B-Algorithm
has	O
an	O
eight-round	O
substitution	B-Algorithm
–	I-Algorithm
permutation	I-Algorithm
network	I-Algorithm
structure	O
similar	O
to	O
that	O
of	O
SHARK	B-Algorithm
,	O
a	O
forerunner	O
to	O
Rijndael	B-Algorithm
.	O
</s>
<s>
The	O
design	O
is	O
classed	O
as	O
a	O
"	O
legacy-level	O
"	O
algorithm	O
,	O
with	O
a	O
64-bit	O
block	O
size	O
(	O
in	O
common	O
with	O
older	O
ciphers	B-Application
such	O
as	O
DES	B-Algorithm
and	O
IDEA	B-Algorithm
)	O
and	O
a	O
128-bit	O
key	O
.	O
</s>
<s>
KHAZAD	B-Algorithm
makes	O
heavy	O
use	O
of	O
involutions	B-Algorithm
as	O
subcomponents	O
;	O
this	O
minimises	O
the	O
difference	O
between	O
the	O
algorithms	O
for	O
encryption	O
and	O
decryption	O
.	O
</s>
<s>
The	O
authors	O
have	O
stated	O
that	O
,	O
"	O
KHAZAD	B-Algorithm
is	O
not	O
(	O
and	O
will	O
never	O
be	O
)	O
patented	O
.	O
</s>
<s>
Frédéric	O
Muller	O
has	O
discovered	O
an	O
attack	O
which	O
can	O
break	O
five	O
of	O
KHAZAD	B-Algorithm
's	O
eight	O
rounds	O
.	O
</s>
