Or just go directly to 2^256 and have enough links for every atom in the observable universe. More importantly, it's enough links that at the Landauer limit a

Or just go directly to 2^256 and have enough links for every atom in the observable universe. More importantly, it's enough links that at the Landauer limit a collision can't happen without consuming ~300,000 solar systems of energy, vastly beyond human technological ability. With this property, each link can also be considered private.