CBDC Tokens based on Zeto

The code for this tutorial can be found in example/zeto.

This shows how to leverage the Zeto in order to build a wholesale CBDC with privacy, illustrating multiple aspects of Paladin's privacy capabilities.

Running the example

Follow the Getting Started instructions to set up a Paldin environment, and then follow the example README to run the code.

Explanation

Below is a walkthrough of each step in the example, with an explanation of what it does.

Create CBDC token

const zetoFactory = new ZetoFactory(paladin3, 'zeto');
const zetoCBDC = await zetoFactory.newZeto(cbdcIssuer, {
  tokenName: 'Zeto_AnonNullifier',
});

This creates a new instance of the Zeto domain, using the Zeto_AnonNullifier contract. This results in a new cloned contract on the base ledger, with a new unique address. This Zeto token contract will be used to represent tokenized cash/CBDC.

The token will be minted by the central bank/CBDC issuer party. Minting is restricted to be requested only by the central bank, the deployer account of the contract.

Issue cash

let receipt = await zetoCBDC.mint(cbdcIssuer, {
  mints: [
    {
      to: bank1,
      amount: 100000,
    },
    {
      to: bank2,
      amount: 100000,
    },
  ],
});

The cash issuer mints cash to the commercial banks, bank1 and bank2.

Bank1 transfers tokens to bank2 as payment

receipt = await zetoCBDC.using(paladin1).transfer(bank1, {
  transfers: [
    {
      to: bank2,
      amount: 1000,
    },
  ],
});

Bank1 can call the transfer function to transfer zeto tokens to multiple parties, up to 10. Note that the identity bank1 exists on the paladin1 instance, therefore it must use that instance to send the transfer transction (.using(paladin1)).