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

Change-Id: I28790c276906ac14ce9f5b10ebd8602ab1de0aae