leading zeroes. func (x *Nat) setBig(n *big.Int) *Nat { limbs := n.Bits() x.reset(len(limbs)) for i := range limbs { x.limbs[i] = uint(limbs[i]) } return x } func (n *Nat) asBig() *big.Int { bits := make([]big.Word, len(n.limbs)) for i := range n.limbs { bits[i] = big.Word(n.limbs[i]) } return new(big.Int).SetBits(bits) } func (n *Nat) String() string { var limbs []string for i := range n.limbs { limbs = append(limbs, fmt.Sprintf("%016X", n.limbs[len(n.limbs)-1-i])) } return "{" + strings.Join(limbs,...