<s>
In	O
cryptography	O
,	O
E2	B-Algorithm
is	O
a	O
symmetric	B-Algorithm
block	O
cipher	O
which	O
was	O
created	O
in	O
1998	O
by	O
NTT	O
and	O
submitted	O
to	O
the	O
AES	O
competition	O
.	O
</s>
<s>
Like	O
other	O
AES	O
candidates	O
,	O
E2	B-Algorithm
operates	O
on	O
blocks	O
of	O
128	O
bits	O
,	O
using	O
a	O
key	O
of	O
128	O
,	O
192	O
,	O
or	O
256	O
bits	O
.	O
</s>
<s>
It	O
uses	O
a	O
12-round	O
Feistel	B-Algorithm
network	I-Algorithm
.	O
</s>
<s>
E2	B-Algorithm
has	O
an	O
input	O
transformation	O
and	O
output	O
transformation	O
that	O
both	O
use	O
modular	O
multiplication	O
,	O
but	O
the	O
round	O
function	O
itself	O
consists	O
only	O
of	O
XORs	B-Application
and	O
S-box	B-Algorithm
lookups	O
.	O
</s>
<s>
The	O
single	O
8×	O
8-bit	O
S-box	B-Algorithm
is	O
constructed	O
from	O
the	O
composition	O
of	O
an	O
affine	B-Algorithm
transformation	I-Algorithm
with	O
the	O
discrete	O
exponentiation	O
x127	O
over	O
the	O
finite	O
field	O
GF(28 )	O
.	O
</s>
<s>
NTT	O
adopted	O
many	O
of	O
E2	B-Algorithm
's	O
special	O
characteristics	O
in	O
Camellia	B-Algorithm
,	O
which	O
has	O
essentially	O
replaced	O
E2	B-Algorithm
.	O
</s>
