International Association for Cryptologic Research

International Association
for Cryptologic Research

IACR News item: 21 July 2015

Oscar Reparaz, Sujoy Sinha Roy, Frederik Vercauteren, Ingrid Verbauwhede
ePrint Report ePrint Report
Lattice-based cryptography has been proposed as a postquantum public-key cryptosystem. In this paper, we present a masked ring-LWE decryption implementation resistant to first-order side-channel attacks. Our solution has the peculiarity that the entire computation is performed in the masked domain. This is achieved thanks to a new, bespoke masked decoder implementation. The output of the ring-LWE decryption are Boolean shares suitable for derivation of a symmetric key. We have implemented a hardware architecture of the masked ring-LWE processor on a Virtex-II FPGA, and have performed side channel analysis to confirm the soundness of our approach. The area of the protected architecture is around $2000$ LUTs, a $20\\%$ increase with respect to the unprotected architecture. The protected implementation takes $7478$ cycles to compute, which is only a factor $\\times2.6$ larger than the unprotected implementation.

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