Current Projects
Hardware Security
New Directions
Algebraic Side-Channel Attack
Algebraic side-channel attack (ASCA) is a powerful cryptanalysis
technique different from conventional side-channel attacks. This
project studies ASCA from three aspects: enhancement, analysis and
application. To enhance ASCA, we propose a generic method, called
Multiple Deductions-based ASCA (MDASCA), to cope the multiple deductions
caused by inaccurate measurements or interferences. For the
first time, we show that ASCA can exploit cache leakage models. We
analyze the attacks and estimate the minimal amount of leakages required
for a successful ASCA on AES under different leakage models. In
addition, we apply MDASCA to attack AES on an 8-bit microcontroller
under Hamming weight leakage model, on two typical microprocessors
under access driven cache leakage model, and on a 32-bit ARM microprocessor
under trace driven cache leakage model. Many better results
are achieved compared to the previous work. The results are also consistent
with the theoretical analysis. Our work shows that MDASCA poses
great threats with its excellence in error tolerance and new leakage model
exploitation.
Algebraic Fault Analysis
Piccolo is a 64-bit lightweight block cipher that is designed
for resource-constrained environments. This paper proposes a new fault
attack on Piccolo using the technique of algebraic fault analysis (AFA).
The attack combines algebraic cryptanalysis with di erential fault analysis,
and constructs a system of algebraic equations for both the cipher
and the injected faults. Using the observed faulty output, an automatic
solver can solve the equation system for the secret key. A major contribution
of this project is to represent the injected faults with algebraic
equations for AFA when the accurate fault location is unknown. Based on
a random nibble fault model in the 23rd round, our AFA can recover the
full key of Piccolo-80 using only a single fault injection within ve hours
on a PC. In addition, our AFA can be applied in other scenarios, such as
the 8-bit and 16-bit fault models with a single fault injection, deep fault
models in the 22nd round with two fault injections, and Piccolo-128 with
three fault injections.
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