Abstract: Scalar multiplication, which computes dP for a given point P and a
scalar d, is the dominant computation part of Elliptic Curve Cryptosystems
(ECC). Recently, Side Channel Attacks (SCA) on scalar multiplication have
become real threats.
This is why secure and efficient scalar multiplication is important for ECC,
and many countermeasures have been proposed so far.
The Montgomery Ladder and the Joye's Regular right-to-left algorithm are
the simplest
and the most elegant algorithms. However, they are vulnerable to
an SCA on the Least Significant Bit (LSB).
In this talk, we investigate how to enhance the LSB security without
spoiling
the original features of simplicity.
Our elegant techniques make the previous schemes secure against the SCA
on LSB, while maintaining original performances.
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