kaidokert / krabiecdsa-rs / 29217478233

94%

Build Type

push

github

Committed by web-flow

Commit Message

Constant-time scalar multiply for signing (RCB complete formulas) (#18)

* Constant-time scalar multiply for signing (RCB complete formulas)

The secret-dependent half of signing now runs constant-time. k·G goes
through Renes-Costello-Batina complete addition (Algorithm 1, arbitrary
a — translated step-for-step from RustCrypto's primeorder), which is
exception-free, so the scalar-multiply ladder is double-and-add-always
with a branchless cswap selecting the add result on set bits: identical
operations every iteration, no timing signal about the scalar. k⁻¹ and
s run through modmath's FieldCt. All of it is on the Ct-personality
backend.

Coverage Stats

152 of 160 new or added lines in 1 file covered. (95.0%)

28 existing lines in 1 file now uncovered.

564 of 593 relevant lines covered (95.11%)

26837.47 hits per line