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point_add

arcana::ecc::curve

Function point_add 

Source 
pub fn point_add<const LIMBS: usize>(
    p_pt: &JacobianPoint<LIMBS>,
    q_pt: &JacobianPoint<LIMBS>,
    params: &CurveParams<LIMBS>,
) -> JacobianPoint<LIMBS>
Expand description

Jacobian point addition: P + Q. Uses the generic “add-2007-bl” formula (no assumption on Z coordinates).

Not constant-time: branches on whether P == Q (to delegate to point_double) and on whether P == -Q (to short-circuit to infinity). Intended for operations on public points only, such as the Shamir trick in double_scalar_mul used by ECDSA verify.

For the CT-critical scalar multiplication path (signing, ECDH), use point_add_ct which is uniform over all P, Q but requires the caller to respect the Montgomery ladder invariant R1 - R0 == P so that P == Q can never occur (the only case the CT variant cannot handle via the generic formulas alone).

Reference: https://www.hyperelliptic.org/EFD/g1p/auto-shortw-jacobian.html#addition-add-2007-bl