func natBytes(n *Nat) []byte {
	return n.Bytes(maxModulus(uint(len(n.limbs))))
}

func natFromBytes(b []byte) *Nat {
	// Must not use Nat.SetBytes as it's used in TestSetBytes.
	bb := new(big.Int).SetBytes(b)
	return NewNat().setBig(bb)
}

func modulusFromBytes(b []byte) *Modulus {
	bb := new(big.Int).SetBytes(b)
	m, _ := NewModulusFromBig(bb)
	return m
}