DO NOT MERGE
Compute ECDSA modular inverses with Fermal's Little Theorem.

This is a partial cherry-pick of
18954938684e269ccd59152027d2244040e2b819.

Bug: 33752052
Change-Id: Iddba4b931f88d2a0d2f7b9b1904b294fff1d8501
(cherry picked from commit 1f170d0b00fbf42c023c3746dd36eb96115e2a6e)
3 files changed