Compute ECDSA modular inverses with Fermal's Little Theorem. am: 1f170d0b00 am: 10c2234fb3 am: 77658a7f05 am: 14b44d83f2  -s ours am: 714afb8f3d am: a968399736
am: 1b75e28e6e

Change-Id: I22aee5a9b79414fb34002eb9650ccd1adcf02057