modular inversion with prime modulus by Fermat's Little // Theorem: qInv = q⁻¹ mod p = q^(p-2) mod p. if p.Nat().IsOdd() == 0 { // [bigmod.Nat.Exp] requires an odd modulus. return nil, errors.New("crypto/rsa: p is even") } pMinusTwo := p.Nat().SubOne(p).SubOne(p).Bytes(p) qInv := bigmod.NewNat().Mod(q.Nat(), p) qInv.Exp(qInv, pMinusTwo, p) pk := &PrivateKey{ pub: PublicKey{ N: n, E: e, }, d: d, p: p, q: q, dP: dP, dQ: dQ, qInv: qInv, } if err := checkPrivateKey(pk); err != nil { return nil, err } return...