-
Billy Brumley authored
This commit leverages the Montgomery ladder scaffold introduced in #6690 (alongside a specialized Lopez-Dahab ladder for binary curves) to provide a specialized differential addition-and-double implementation to speedup prime curves, while keeping all the features of `ec_scalar_mul_ladder` against SCA attacks. The arithmetic in ladder_pre, ladder_step and ladder_post is auto generated with tooling, from the following formulae: - `ladder_pre`: Formula 3 for doubling from Izu-Takagi "A fast parallel elliptic curve multiplication resistant against side channel attacks", as described at https://hyperelliptic.org/EFD/g1p/auto-shortw-xz.html#doubling-dbl-2002-it-2 - `ladder_step`: differential addition-and-doubling Eq. (8) and (10) from Izu-Takagi "A fast parallel elliptic curve multiplication resistant against side channel attacks", as described at https://hyperelliptic.org/EFD/g1p/auto-shortw-xz.html#ladder-ladd-2002-it-3 - `ladder_post`: y-coordinate recovery using Eq. (8) from Brier-Joye "Weierstrass Elliptic Curves and Side-Channel Attacks", modified to work in projective coordinates. Co-authored-by: Nicola Tuveri <nic.tuv@gmail.com> Reviewed-by: Andy Polyakov <appro@openssl.org> Reviewed-by: Rich Salz <rsalz@openssl.org> (Merged from https://github.com/openssl/openssl/pull/6772)
9d91530d
To find the state of this project's repository at the time of any of these versions, check out the tags.