Hardware implementation of DBNS recoding for ECC processor

The paper presents arithmetic level protections for ECC processor against some side channel attacks. The proposed protection is based on random recodings of the secret key in the double base number system (DBNS). DBNS is a highly redundant and sparse number system. Here, the high redundancy level of DBNS is used to randomly modify on-the-fly the k_i digits during the scalar multiplication [k]P. The proposed solution leads to random numbers and orders of curve level operations (point addition, doubling and tripling) during the computation of [k]P operations. Our random recoding method provides [k]P computation time comparable to the best w-NAF recoding methods. But standard w-NAF recodings are deterministic ones while our solution is a random one.