<s>
In	O
cryptography	O
,	O
SXAL	B-Algorithm
(	O
Substitution	O
Xor	B-Application
ALgorithm	O
,	O
sometimes	O
called	O
SXAL8	B-Algorithm
)	O
is	O
a	O
block	O
cipher	O
designed	O
in	O
1993	O
by	O
Yokohama-based	O
Laurel	O
Intelligent	O
Systems	O
.	O
</s>
<s>
It	O
is	O
normally	O
used	O
in	O
a	O
special	O
mode	B-Algorithm
of	I-Algorithm
operation	I-Algorithm
called	O
MBAL	B-Algorithm
(	O
Multi	O
Block	O
ALgorithm	O
)	O
.	O
</s>
<s>
SXAL/MBAL	B-Algorithm
has	O
been	O
used	O
for	O
encryption	O
in	O
a	O
number	O
of	O
Japanese	O
PC	B-Architecture
cards	I-Architecture
and	O
smart	O
cards	O
.	O
</s>
<s>
SXAL	B-Algorithm
is	O
an	O
8-round	O
substitution	B-Algorithm
–	I-Algorithm
permutation	I-Algorithm
network	I-Algorithm
with	O
block	O
size	O
and	O
key	O
size	O
of	O
64	O
bits	O
each	O
.	O
</s>
<s>
The	O
algorithm	O
uses	O
a	O
single	O
8×	O
8-bit	O
S-box	B-Algorithm
K	O
,	O
designed	O
so	O
that	O
both	O
K(X )	O
and	O
X	O
XOR	B-Application
K(X )	O
are	O
injective	O
functions	O
.	O
</s>
<s>
Then	O
each	O
byte	O
is	O
XORed	O
with	O
a	O
key	O
byte	O
and	O
an	O
earlier	O
ciphertext	O
byte	O
,	O
processed	O
through	O
the	O
S-box	B-Algorithm
,	O
and	O
XORed	O
with	O
the	O
previous	O
plaintext	O
byte	O
.	O
</s>
<s>
The	O
key	B-Algorithm
schedule	I-Algorithm
is	O
rather	O
complex	O
,	O
processing	O
the	O
key	O
with	O
SXAL	B-Algorithm
itself	O
,	O
beginning	O
with	O
a	O
null	O
key	O
and	O
using	O
permuted	O
intermediate	O
results	O
as	O
later	O
keys	O
.	O
</s>
<s>
MBAL	B-Algorithm
is	O
an	O
encryption	O
algorithm	O
built	O
using	O
SXAL	B-Algorithm
that	O
can	O
be	O
applied	O
to	O
messages	O
any	O
number	O
of	O
bytes	O
in	O
length	O
(	O
at	O
least	O
8	O
)	O
.	O
</s>
<s>
It	O
uses	O
two	O
64-bit	O
extended	O
keys	O
for	O
key	B-Algorithm
whitening	I-Algorithm
on	O
the	O
first	O
64	O
bits	O
.	O
</s>
<s>
MBAL	B-Algorithm
has	O
been	O
shown	O
to	O
be	O
susceptible	O
to	O
both	O
differential	O
cryptanalysis	O
and	O
linear	O
cryptanalysis	O
.	O
</s>
