How to Make It Harder for the Bank to Produce Two Money States on Its Own

In quantum-money, we have this bank which holds on to a secret when preparing the money state. We can make it even hard for the bank to produce two money states with the same zero number. And so, if you try to double spend, you're not able to do that because all the zero numbers are that keep track somewhere. This procedure of generating quantum money states is completely public. You simply have to use some public randomness,. Some sort of randomly speaking, some trusted randomness resource out there. But once you public the CCR number out there, okay, it's fixed, and you are not able to doing that twice.