Cryptography Reference
In-Depth Information
P
laintext
i n
128
secret key (128 bits)
P
l
a
n
t
t
1
2
8
substitute bytewise
e
x
i
n
i
key of
round
1
rotate lines cyclically
round 1
key of
round
2
mix columns individually
round 2
.
.
.
.
XOR round's key
.
.
.
round 10
key of
round
10
$ *
ä
x
-
\
§
^
{
:
C
g
ü S .
!
$
*x-
ä
\
§
^:
{
CgüS!
.
Figure 5.20:
Basic representation of Rijndael.
-
ByteSub
: The single bytes of the state matrix are substituted by a fixed
scheme. This transformation is deterministic and known, so it doesn't
represent an encryption yet.
-
ShiftRow
: The rows of the state are cyclically left-rotated bytewise by
0, 1, 2, and 3 bytes. For example, if the characters
abcd
are in row 2, then this row looks like this after the
ShiftRow
transfor-
mation:
bcda
Naturally this transformation is deterministic and doesn't encrypt any-
thing.
