Cryptography Reference
In-Depth Information
25
Temporal localization
20
15
10
5
0
Round
Fig. 17.9
Temporal localization of single faults
30
Spatial localization
25
20
15
10
5
0
Sbox
Fig. 17.10
Spatial localization of single faults. The SubBytes S-box
s
i
,
j
has index 4
×
i
+
j
in the
PMF histogram
studied architecture. However, there is no reason for those S-Boxes to be synthesized
or to be placed and routed in exactly the same manner. This is one cause of spatial
heterogeneity (Fig.
17.10
). Second, the temporal heterogeneity (Fig.
17.9
) could be
ascribed to the time between two consecutive faults. For instance, if this average time
is close to half the encryption duration, then it is likely that a fault occurring in the first
rounds is followed by another fault in the subsequent rounds. Similarly, a single fault
in the last rounds is rare since it is highly probable that another fault actually happened
