- pmul_ct: double-and-add-always over the Renes–Costello–Batina complete
projective addition formula (Alg. 4, a=-3) — one exception-free formula for
add and double, identity (0:1:0), so there is NO point-at-infinity branch.
Closes the documented residual: the Jacobian jadd/jdouble ladder's fp_zero
checks leaked k's leading-zero count (a bit-length hint) during ECDSA sign
- wo_ecdsa_p256_sha256_sign uses it; affine x = X * Z^-1 (projective), the
inversion via the constant-time modexp. Dead Jacobian jmul_ct/jpt_cmov removed
- RFC 6979 A.2.5 vectors still byte-exact (test_crypto 130/0); server loopback
(signs with this ladder) still green (test_tls 123/0); ASan/UBSan clean
- docs: rv2 9 review_pending — close_notify + complete-formula ladder moved
from deferred to landed; lang-41 decision 4 fixture marked landed
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
(cherry picked from commit fba30352b965e0f3b749168421a920a832df541b)
shoney.arickathil
3b1a188d77