Reference Application: Central Bank Digital Currency (CBDC)

• Overview
• Getting Started with Sandbox
  • Installing
  • Prerequisites
  • Starting the App
  • Stopping the App
  • Resetting the Prototype
  • Resetting the Prototype with the Experimental Reset Service
• Getting Started with Daml Hub
• Getting Started with Canton
• Running the Demo
• Notes for Developers
  • Model
  • Debugging with Navigator

Overview

Refer to the User Guide for details on the features shown in this application along with detailed instructions on running the demo.

The demo shows how Daml supports core features of CBDC, addressing these key requirements:

• Tracking: Daml supports auditing and tracking transactions and storing contracts along with the history of each transaction. Observers of a Daml contract can be customized to allow for more transparency and visibility.
• Controls: An authority controls who can own money at a programmatic level, for example, to comply with restricted lists (e.g., OFAC).
• Safety: For simple or complicated transactions, Daml can establish specific rules for money transfers that must be met atomically (e.g., all steps must be successful) for the transaction to occur.
• Interoperability: Daml would permit a CBDC system to bridge different ledgers and technologies.

Getting Started with Sandbox

Installing

Disclaimer: This reference application is intended to demonstrate the capabilities of Daml. We recommend that you consider other non-functional aspects, such as security, resiliency, recoverability, etc., prior to production use.

Prerequisites

• Daml SDK
• Make
• Python 3
• Node v14

Starting the App

1. To build the App, enter:

   make build

   Notes:

   • If you change the DAML models locally, you need to re-run this command before starting the application.
   • See the Makefile for other available targets.

2. Use separate terminals to launch the individual components:

   launchers/sandbox
   launchers/jsonapi
   launchers/automation
   launchers/ui

3. Use the following script to initialize the ledger:

   launchers/populate
   

The demo will run at http://localhost:3000

Stopping the App

1. Stop the every running command by pressing Ctrl+C.

Resetting the Prototype

To reset the application:

1. Stop the app by following the steps in Stopping the App section.
2. Start the app by following the steps in Starting the App section.

Resetting the Prototype with the Experimental Reset Service

Note: we only provide reset instructions for Sandbox. It can easily be configured for any other infrastructure.

1. Start the reset service. Use the adequate party-participant configs. For example when working with Sandbox use the following:

   launchers/resetService parties.json default_participant_config.cfg
   

   Note: the parties.json file is created when the ledger is initialized.

2. Click on the Reload button.

Getting Started with Daml Hub

1. Create a project and a ledger on Daml Hub

2. Add the parties to the ledger

   • Alice
   • BankA
   • BankB
   • DemoAdmin
   • ECB
   • Landlord
   • LandlordsAssociation
   • USFRB

3. Download participants.json from the ledger settings to the ui folder

4. Download the parties.json from the users tab to the ui folder

5. Build the DABL version of the project

   make daml-hub-package LEDGER_ID=[Ledger ID]

   The ledger ID can be found on the ledger settings.

6. Upload the artifacts and deploy them to the ledger

   • testing/.daml/dist/testing-1.0.0.dar
   • triggers/.daml/dist/triggers-1.0.0.dar
   • reset/.daml/dist/reset-1.0.0.dar
   • ui/cbdc-ui.zip

7. Run the ledger setup

   scripts/ledger-setup.sh ui/participants.json ui/dabl-parties.json --json-api

The demo will run at the location provided by Daml Hub.

Getting Started with Canton

Make sure Canton is installed and canton can be found in the PATH. Launch Canton and wait until it fully starts in order to have the generated configs:

launchers/canton/ledgers

After you see the message Welcome to Canton!, launch everything else:

launchers/canton/populate && launchers/canton/automation
launchers/canton/jsonapis
launchers/canton/ui

The demo will run in http://localhost:3000

Running the Demo

Refer to the User Guide for instructions on running the demo.

Notes for Developers

Model

For each DVP, the model creates a dedicated a settlement rule and an instruction. The DVP ID assumes that there can only be USD-EUR trades. Settlement rules also have IDs based on the master agreement. See the Daml templates for details.

Debugging with Navigator

Visualization using Navigator (development UI):

daml navigator server localhost 6865 --port 7500

Then open http://localhost:7500.

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