31 Oct
2019
31 Oct
'19
12:07 p.m.
Hello,
I've noticed the following typical code sequence:
ecc_modp_mul(ecc, t, x, y); cy = mpn_sub_n(dest, t, ecc->p.m, ecc->p.size); cnd_copy(cy, dest, t, ecc->p.size);
What is the benefit of this piece of code over the following one?
ecc_modp_mul(ecc, t, x, y); memcpy(dest, t, ecc->p.size * sizeof(mp_limb_t));
Does mpn_sun_n/cnd_copy add any form of side channel attach protection?
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With best wishes
Dmitry