Cryptography Reference
In-Depth Information
Fig. 6.
Truncated differential trail for 8 rounds of Square for chosen-key distinguisher
(
σ
=
σ
(
θ
(
k
0
)))
B
Truncated Differential Trail for Modified mCrypton
The key scheduling in the test implementation of mCrypton has been adopted
from Crypton and has following way:
Let
K
be a 128-bit encryption key and
K
=
k
0
...k
31
where each
k
i
is four-
bit nibble for
i
=0
,...,
31. At first two temporal values
U
and
V
are derived
from
K
so that
U
[
i
]=
k
8
i
k
8
i
+2
k
8
i
+4
k
8
i
+6
and
V
[
i
]=
k
8
i
+1
k
8
i
+3
k
8
i
+5
k
8
i
+7
for
i
=0
,
1
,
2
,
3. Next for
U
=
γ
(
U
)and
V
=
γ
(
V
) the eight expanded keys are
evaluated as:
E
[
i
]=
j
E
[
i
+4]=
j
U
[
j
]
V
[
j
]
=
i
=
i
for
i
=0
,
1
,
2
,
3 with use of which the 13 subkeys for each encryption round are
generated according to the following procedure:
Fig. 7.
Standard differential trail for 6.5 rounds of SAFER++ for chosen-key distin-
guisher and 128-bit key
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