<s>
In	O
computer	B-General_Concept
science	I-General_Concept
and	O
cryptography	O
,	O
Whirlpool	B-Algorithm
(	O
sometimes	O
styled	O
WHIRLPOOL	B-Algorithm
)	O
is	O
a	O
cryptographic	B-Algorithm
hash	I-Algorithm
function	I-Algorithm
.	O
</s>
<s>
It	O
was	O
designed	O
by	O
Vincent	O
Rijmen	O
(	O
co-creator	O
of	O
the	O
Advanced	B-Algorithm
Encryption	I-Algorithm
Standard	I-Algorithm
)	O
and	O
Paulo	O
S	O
.	O
L	O
.	O
M	O
.	O
Barreto	O
,	O
who	O
first	O
described	O
it	O
in	O
2000	O
.	O
</s>
<s>
The	O
hash	B-Algorithm
has	O
been	O
recommended	O
by	O
the	O
NESSIE	O
project	O
.	O
</s>
<s>
It	O
has	O
also	O
been	O
adopted	O
by	O
the	O
International	O
Organization	O
for	O
Standardization	O
(	O
ISO	O
)	O
and	O
the	O
International	O
Electrotechnical	O
Commission	O
(	O
IEC	O
)	O
as	O
part	O
of	O
the	O
joint	O
ISO/IEC	B-Algorithm
10118-3	I-Algorithm
international	O
standard	O
.	O
</s>
<s>
Whirlpool	B-Algorithm
is	O
a	O
hash	B-Algorithm
designed	O
after	O
the	O
Square	B-Algorithm
block	O
cipher	O
,	O
and	O
is	O
considered	O
to	O
be	O
in	O
that	O
family	O
of	O
block	O
cipher	O
functions	O
.	O
</s>
<s>
Whirlpool	B-Algorithm
is	O
a	O
Miyaguchi-Preneel	O
construction	O
based	O
on	O
a	O
substantially	O
modified	O
Advanced	B-Algorithm
Encryption	I-Algorithm
Standard	I-Algorithm
(	O
AES	B-Algorithm
)	O
.	O
</s>
<s>
Whirlpool	B-Algorithm
takes	O
a	O
message	O
of	O
any	O
length	O
less	O
than	O
2256	O
bits	O
and	O
returns	O
a	O
512-bit	O
message	B-Algorithm
digest	I-Algorithm
.	O
</s>
<s>
"	O
WHIRLPOOL	B-Algorithm
is	O
not	O
(	O
and	O
will	O
never	O
be	O
)	O
patented	O
.	O
</s>
<s>
The	O
original	O
Whirlpool	B-Algorithm
will	O
be	O
called	O
Whirlpool-0	O
,	O
the	O
first	O
revision	O
of	O
Whirlpool	B-Algorithm
will	O
be	O
called	O
Whirlpool-T	O
and	O
the	O
latest	O
version	O
will	O
be	O
called	O
Whirlpool	B-Algorithm
in	O
the	O
following	O
test	O
vectors	O
.	O
</s>
<s>
In	O
the	O
first	O
revision	O
in	O
2001	O
,	O
the	O
S-box	B-Algorithm
was	O
changed	O
from	O
a	O
randomly	O
generated	O
one	O
with	O
good	O
cryptographic	O
properties	O
to	O
one	O
which	O
has	O
better	O
cryptographic	O
properties	O
and	O
is	O
easier	O
to	O
implement	O
in	O
hardware	O
.	O
</s>
<s>
In	O
the	O
second	O
revision	O
(	O
2003	O
)	O
,	O
a	O
flaw	O
in	O
the	O
diffusion	B-General_Concept
matrix	I-General_Concept
was	O
found	O
that	O
lowered	O
the	O
estimated	O
security	O
of	O
the	O
algorithm	O
below	O
its	O
potential	O
.	O
</s>
<s>
The	O
Whirlpool	B-Algorithm
hash	I-Algorithm
function	O
is	O
a	O
Merkle	B-Algorithm
–	I-Algorithm
Damgård	I-Algorithm
construction	I-Algorithm
based	O
on	O
an	O
AES-like	O
block	O
cipher	O
W	O
in	O
Miyaguchi	O
–	O
Preneel	O
mode	O
.	O
</s>
<s>
The	O
SubBytes	O
operation	O
applies	O
a	O
non-linear	O
permutation	O
(	O
the	O
S-box	B-Algorithm
)	O
to	O
each	O
byte	O
of	O
the	O
state	O
independently	O
.	O
</s>
<s>
The	O
8-bit	O
S-box	B-Algorithm
is	O
composed	O
of	O
3	O
smaller	O
4-bit	O
S-boxes	B-Algorithm
.	O
</s>
<s>
The	O
Whirlpool	B-Algorithm
algorithm	O
has	O
undergone	O
two	O
revisions	O
since	O
its	O
original	O
2000	O
specification	O
.	O
</s>
<s>
People	O
incorporating	O
Whirlpool	B-Algorithm
will	O
most	O
likely	O
use	O
the	O
most	O
recent	O
revision	O
of	O
Whirlpool	B-Algorithm
;	O
while	O
there	O
are	O
no	O
known	O
security	O
weaknesses	O
in	O
earlier	O
versions	O
of	O
Whirlpool	B-Algorithm
,	O
the	O
most	O
recent	O
revision	O
has	O
better	O
hardware	O
implementation	O
efficiency	O
characteristics	O
,	O
and	O
is	O
also	O
likely	O
to	O
be	O
more	O
secure	O
.	O
</s>
<s>
As	O
mentioned	O
earlier	O
,	O
it	O
is	O
also	O
the	O
version	O
adopted	O
in	O
the	O
ISO/IEC	B-Algorithm
10118-3	I-Algorithm
international	O
standard	O
.	O
</s>
<s>
The	O
512-bit	O
(	O
64-byte	O
)	O
Whirlpool	B-Algorithm
hashes	I-Algorithm
(	O
also	O
termed	O
message	B-Algorithm
digests	I-Algorithm
)	O
are	O
typically	O
represented	O
as	O
128-digit	O
hexadecimal	O
numbers	O
.	O
</s>
<s>
The	O
following	O
demonstrates	O
a	O
43-byte	O
ASCII	B-Protocol
input	O
(	O
not	O
including	O
quotes	O
)	O
and	O
the	O
corresponding	O
Whirlpool	B-Algorithm
hashes	I-Algorithm
:	O
</s>
<s>
Even	O
a	O
small	O
change	O
in	O
the	O
message	O
will	O
(	O
with	O
an	O
extremely	O
high	O
probability	O
of	O
)	O
result	O
in	O
a	O
different	O
hash	B-Algorithm
,	O
which	O
will	O
usually	O
look	O
completely	O
different	O
just	O
like	O
two	O
unrelated	O
random	O
numbers	O
do	O
.	O
</s>
<s>
The	O
following	O
demonstrates	O
the	O
result	O
of	O
changing	O
the	O
previous	O
input	O
by	O
a	O
single	O
letter	O
(	O
a	O
single	O
bit	O
,	O
even	O
,	O
in	O
ASCII-compatible	O
encodings	O
)	O
,	O
replacing	O
with	O
:	O
</s>
<s>
The	O
hash	B-Algorithm
of	O
a	O
zero-length	O
string	O
is	O
:	O
</s>
<s>
The	O
authors	O
provide	O
reference	O
implementations	O
of	O
the	O
Whirlpool	B-Algorithm
algorithm	O
,	O
including	O
a	O
version	O
written	O
in	O
C	B-Language
and	O
a	O
version	O
written	O
in	O
Java	B-Language
.	O
</s>
<s>
Two	O
of	O
the	O
first	O
widely	O
used	O
mainstream	O
cryptographic	O
programs	O
that	O
started	O
using	O
Whirlpool	B-Algorithm
were	O
FreeOTFE	B-Application
,	O
followed	O
by	O
TrueCrypt	B-Application
in	O
2005	O
.	O
</s>
<s>
VeraCrypt	B-Operating_System
(	O
a	O
fork	O
of	O
TrueCrypt	B-Application
)	O
included	O
Whirlpool	B-Algorithm
(	O
the	O
final	O
version	O
)	O
as	O
one	O
of	O
its	O
supported	O
hash	B-Algorithm
algorithms	O
.	O
</s>
