Security Issues in QCA Circuit Design - Power Analysis Attacks - Field-Coupled Nanocomputing: Paradigms, Progress, and Perspectives - page 204

Table 3. Power consumption of a majority gate with different tunnelling energy levels
( T =2 . 0K)

Switching Hamming Power dissipated

(A, B, C) distance γ =0 . 25 E k γ =0 . 5 E k γ =0 . 75 E k γ =1 . 0 E k

(meV) (meV) (meV) (meV)

000 → 000 (0) 0 0.8 2.8 5.3 8.1

000 → 001 (1) 1 2.3 4.2 6.8 9.8

000 → 010 (2) 2.3 4.2 6.8 9.8

000 → 100 (4) 2.3 4.2 6.8 9.7

000 → 011 (3) 2 25.3 26.4 27.9 29.8

000 → 101 (5) 25.3 26.4 28.0 29.8

000 → 110 (6) 25.3 26.4 28.0 29.8

000 → 111 (7) 3 41.0 41.2 41.9 42.9

45

40

γ =1.0E k

γ =0.75E k

35

γ =0.5E k

30

γ =0.25E k

25

20

15

10

5

0

0 1 2 3

Hamming Distance

Fig. 10. Power consumption ( T =2 . 0 K) in majority gate versus Hamming distance
with various tunneling energy γ levels.

temperature range of current semiconductor QCA devices is limited, there is
little power consumption difference for different temperatures.
As power analysis attacks exploit the fact that the power consumption of a
cryptographic circuit is correlated with the processed data, such as the HD of
inputs [ 32 ], from the analysis outlined above, QCA cryptographic circuits may
be vulnerable to attack. However, since QCA architectures are very different
from equivalent CMOS architectures, the vulnerability is further studied by per-
forming a power analysis attack on a sub-module of the Serpent cryptographic
algorithm designed in QCA.

3 Design of the QCA Cryptographic Circuit:
Serpent Sub-Module

Cryptographic block ciphers including AES and DES are widely used to encrypt
confidential information. However, they are vulnerable to power analysis attack