  In this paper we report on the results of selected horizontal SCA attacks
against two open-source designs that implement hardware accelerators for
elliptic curve cryptography. Both designs use the complete addition formula to
make the point addition and point doubling operations indistinguishable. One of
the designs uses in addition means to randomize the operation sequence as a
countermeasure. We used the comparison to the mean and an automated SPA to
attack both designs. Despite all these countermeasures, we were able to extract
the keys processed with a correctness of 100%.
