<s>
In	O
cryptography	O
,	O
CIPHERUNICORN-E	B-Algorithm
is	O
a	O
block	O
cipher	O
created	O
by	O
NEC	O
in	O
1998	O
.	O
</s>
<s>
The	O
algorithm	O
has	O
a	O
16-round	O
modified	O
Feistel	B-Algorithm
network	I-Algorithm
structure	O
,	O
with	O
an	O
additional	O
key-dependent	O
mixing	O
function	O
after	O
every	O
2	O
rounds	O
.	O
</s>
<s>
The	O
first	O
part	O
(	O
called	O
the	O
main	O
stream	O
by	O
the	O
designers	O
)	O
consists	O
of	O
XORs	B-Application
and	O
S-box	B-Algorithm
lookups	O
,	O
with	O
a	O
few	O
choices	O
influenced	O
by	O
the	O
second	O
part	O
.	O
</s>
<s>
This	O
second	O
function	O
(	O
called	O
temporary	O
key	O
generation	O
)	O
uses	O
more	O
XORs	B-Application
and	O
two	O
operations	O
which	O
are	O
equivalent	O
to	O
modular	O
multiplications	O
.	O
</s>
<s>
There	O
are	O
4	O
S-boxes	B-Algorithm
in	O
all	O
,	O
each	O
with	O
8-bit	O
inputs	O
and	O
outputs	O
.	O
</s>
<s>
In	O
2000	O
,	O
NEC	O
used	O
the	O
same	O
high-level	O
structure	O
,	O
with	O
more	O
elaborate	O
components	O
,	O
to	O
design	O
the	O
CIPHERUNICORN-A	B-Algorithm
cipher	O
.	O
</s>
<s>
CIPHERUNICORN-E	B-Algorithm
'	O
s	O
key	B-Algorithm
schedule	I-Algorithm
uses	O
a	O
nested	O
Feistel	B-Algorithm
network	I-Algorithm
,	O
based	O
on	O
some	O
of	O
the	O
same	O
building	O
blocks	O
as	O
the	O
cipher	O
itself	O
.	O
</s>
<s>
The	O
complexity	O
of	O
CIPHERUNICORN-E	B-Algorithm
'	O
s	O
round	O
function	O
has	O
made	O
it	O
difficult	O
to	O
analyze	O
.	O
</s>
