iterations of // the Miller-Rabin test. func millerRabinSetup(w []byte) (*millerRabin, error) { mr := &millerRabin{} // Check that w is odd, and precompute Montgomery parameters. wm, err := bigmod.NewModulus(w) if err != nil { return nil, err } if wm.Nat().IsOdd() == 0 { return nil, errors.New("candidate is even") } mr.w = wm // Compute m = (w-1)/2^a, where m is odd. wMinus1 := mr.w.Nat().SubOne(mr.w) if wMinus1.IsZero() == 1 { return nil, errors.New("candidate is one") } mr.a = wMinus1.TrailingZeroBitsVarT()...