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Power analysis attacks (PAAs) have been found to be extremely effective on
cryptographic systems to derive the cryptographic secrets from these
traces.
In this work, Binary Decision Diagram (BDD) based dual-rail logic circuit
schemes have been developed to counter power analysis attacks (PAAs). The
hallmark of our circuit schemes is that an identical number of switchings
is ensured on each circuit path. The transistors are interconnected to
create pull-up and pull-down paths to outputs by way of binary decisions
based on the input variables, so as to realise the required Boolean
function. This principle of operation has directly permitted the use of
BDD based logic synthesis to design the required pull-up and pull-down
networks of transistors. The operation of these circuit schemes feature
novel pre-charge generation, voltage scaling with leakage power
minimization and early propagation effect resistance mechanism. In
particular, we have developed and explored top pre-charging, top-bottom
pre-charging, bottom pre-charging and symmetric NMOS bottom pre-charging
logics. A simple synthesis algorithm for mapping a given Boolean functions
to such BDD based circuits is also presented.
Extensive experimentation has been carried out to establish resistance of
our circuits to PAAs. Objective of the experimentation is two fold, to
demonstrate resistance to power attacks and to highlight the low power
characteristics. Towards the first objective, differential power attacks
such as, difference of mean (DoM) and correlation power attack (CPA) have
been carried out. Resilience to the the early propagation effect (EPE) is
also demonstrated. Six 2-input basic cell and two 4×4 S-boxes are used for
experimental benchmark. Experimental results on circuits with bottom
pre-charge logic demonstrate a significant reduction by 99.68% and 88.55%
in peak power variance (PPV) over two chosen competing designs, for the
basic cell. The reduction in PPV is recorded to be greater than 99.9% for
the S-box implementations for both those design. A reduction of about 30%
to 67% in both average power and average current consumption is observed
while comparing with the chosen techniques. Experimental results on
circuits with various other features such as top pre-charge and top-bottom
pre-charge also demonstrate a large reductions in PPV. Significant
reduction for average power and average current for both the pre-charge
logics is also achieved. Circuits using top-pre charging required less
transistors and demonstrated lower PPV in comparison with others.
Symmetric NMOS bottom pre-charge logic was more resilient to EPE due to its
symmetric nature. Bottom pre-charge and symmetric NMOS bottom pre-charge
logic were also effective in avoiding timing attacks along with top-bottom
pre-charge logic.
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