crypto/ec/curve25519.c: remove redundant fe[51]_cswap.
3 least significant bits of the input scalar are explicitly cleared,
hence swap variable has fixed value [of zero] upon exit from the loop.
@@ -471,8 +471,6 @@ static void x25519_scalar_mult(uint8_t out[32], const uint8_t scalar[32],
fe51_mul(z3, x1, z2);
fe51_mul(z2, tmp1, tmp0);
}
- fe51_cswap(x2, x3, swap);
- fe51_cswap(z2, z3, swap);
fe51_invert(z2, z2);
fe51_mul(x2, x2, z2);
@@ -4050,8 +4048,6 @@ static void x25519_scalar_mult_generic(uint8_t out[32],
fe_mul(z3, x1, z2);
fe_mul(z2, tmp1, tmp0);
}
- fe_cswap(x2, x3, swap);
- fe_cswap(z2, z3, swap);
fe_invert(z2, z2);
fe_mul(x2, x2, z2);
