Canton ERC-20 Bridge - Daml Contracts

Daml smart contracts for bridging ERC-20 tokens between Ethereum and Canton Network

This repository contains the Daml implementation of a token bridge connecting ERC-20 tokens on Ethereum with CIP-56 compliant tokens on Canton Network. The Go middleware implementation is maintained in the parent canton-middleware repository.

Production Status

Bridge	Token	Status	Network
Wayfinder	PROMPT	Production Ready	5North DevNet / Mainnet
USDC	USDC	In Development	—
cBTC	cBTC	In Development	—
Generic	Any ERC20	In Development	—

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                        CANTON NETWORK                           │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  ┌─────────────┐    ┌─────────────┐    ┌─────────────┐         │
│  │   common    │───>│ cip56-token │───>│ bridge-core │         │
│  │   (types)   │    │  (standard) │    │ (contracts) │         │
│  └─────────────┘    └─────────────┘    └──────┬──────┘         │
│                                               │                 │
│         ┌─────────────────────────────────────┼─────────────┐  │
│         │                    │                │             │  │
│         ▼                    ▼                ▼             ▼  │
│  ┌─────────────┐    ┌─────────────┐   ┌─────────────┐  ┌─────┐│
│  │  wayfinder  │    │    usdc     │   │    cbtc     │  │ ... ││
│  │  (PROMPT)   │    │  (Circle)   │   │  (BitSafe)  │  │     ││
│  │ [PRODUCTION]│    │   [WIP]     │   │    [WIP]    │  │     ││
│  └─────────────┘    └─────────────┘   └─────────────┘  └─────┘│
│                                                                 │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│                      GO MIDDLEWARE                              │
│              (Event Streaming + Command Submission)             │
│                    canton-middleware repo                       │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│                        ETHEREUM                                 │
│                   (ERC-20 + Bridge Contracts)                   │
│                ethereum-wayfinder submodule                     │
└─────────────────────────────────────────────────────────────────┘

Repository Structure

canton-erc20/
├── daml/                               # Daml packages
│   ├── multi-package.yaml              # Workspace configuration
│   │
│   │   # === Core Infrastructure (Production) ===
│   ├── common/                         # Shared types and utilities
│   ├── cip56-token/                    # CIP-56 token standard
│   ├── bridge-core/                    # Core bridge contracts
│   │
│   │   # === Client-Specific Bridges (Production) ===
│   ├── bridge-wayfinder/               # Wayfinder PROMPT (Production)
│   ├── bridge-usdc/                    # USDC (In Development)
│   ├── bridge-cbtc/                    # cBTC (In Development)
│   ├── bridge-generic/                 # Generic ERC20 (In Development)
│   │
│   │   # === Additional Modules (Production) ===
│   ├── dvp/                            # Delivery vs Payment
│   │
│   │   # === Test Packages (with daml-script) ===
│   ├── common-tests/                   # Tests for common
│   ├── cip56-token-tests/              # Tests for cip56-token
│   ├── bridge-core-tests/              # Tests for bridge-core
│   ├── bridge-wayfinder-tests/         # Tests for bridge-wayfinder
│   └── integration-tests/              # End-to-end tests
│
├── docs/                               # Documentation
│   └── DAML_ARCHITECTURE_PROPOSAL.md   # Technical design document
├── CHANGELOG.md                        # Version history
└── README.md                           # This file

Quick Start

Prerequisites

• Daml SDK 3.4.8 - Install Guide

daml version  # Should show 3.4.8

Build All Packages

From the parent canton-middleware repository:

./scripts/build-dars.sh

Or build individually from this directory:

cd daml/common && daml build --no-legacy-assistant-warning
cd ../cip56-token && daml build --no-legacy-assistant-warning
cd ../bridge-core && daml build --no-legacy-assistant-warning
cd ../bridge-wayfinder && daml build --no-legacy-assistant-warning

Run Tests

# Run Wayfinder bridge test
cd daml/bridge-wayfinder-tests
daml script \
  --dar .daml/dist/bridge-wayfinder-tests-1.1.0.dar \
  --script-name Wayfinder.Test:testWayfinderBridge \
  --ide-ledger

Expected output:

>>> Deposit flow complete: Alice has 1000.0 tokens
>>> Withdrawal initiated: 500.0 tokens pending release on EVM
>>> Withdrawal completed on EVM
✓ Bridge flow test completed successfully!

Package Overview

Production Packages

These packages are deployed to Canton Network and do not include daml-script to avoid bloating the package store.

Package	Description	Status
common	Shared types (TokenMeta, EvmAddress, ChainRef, FingerprintAuth)	Stable
cip56-token	CIP-56 compliant token with privacy-preserving transfers	Stable
bridge-core	Issuer-centric bridge contracts (MintCommand, WithdrawalRequest, WithdrawalEvent)	Stable
bridge-wayfinder	Wayfinder PROMPT token bridge	Production
bridge-usdc	Circle USDC bridge	Development
bridge-cbtc	BitSafe cBTC bridge	Development
bridge-generic	Generic ERC20 bridge	Development
dvp	Delivery vs Payment settlement	Development

Test Packages

Test packages include daml-script and are not deployed to production ledgers.

Package	Tests
common-tests	FingerprintAuthTest
cip56-token-tests	Mint, Transfer, Compliance flows
bridge-core-tests	Full bridge cycle
bridge-wayfinder-tests	E2E Wayfinder flow
integration-tests	Cross-package integration

Package Dependency Graph

common                         (no dependencies)
  └── cip56-token             
        └── bridge-core       
              ├── bridge-wayfinder   [PRODUCTION]
              ├── bridge-usdc        [WIP]
              ├── bridge-cbtc        [WIP]
              └── bridge-generic     [WIP]
  └── dvp

Testing

Test Individual Package

# CIP-56 Token tests
cd daml/cip56-token-tests
daml script --dar .daml/dist/cip56-token-tests-1.1.0.dar \
  --script-name CIP56.Script:test --ide-ledger

# Bridge Core tests
cd daml/bridge-core-tests
daml script --dar .daml/dist/bridge-core-tests-1.1.0.dar \
  --script-name Bridge.Script:testBridgeFlow --ide-ledger

# Wayfinder tests
cd daml/bridge-wayfinder-tests
daml script --dar .daml/dist/bridge-wayfinder-tests-1.1.0.dar \
  --script-name Wayfinder.Test:testWayfinderBridge --ide-ledger

Test Coverage

Package	Test Script	Coverage
cip56-token-tests	CIP56.Script:test	Mint, Transfer, Compliance
bridge-core-tests	Bridge.Script:testBridgeFlow	Full bridge cycle
bridge-wayfinder-tests	Wayfinder.Test:testWayfinderBridge	E2E Wayfinder flow

Security & Privacy

All contracts implement Canton privacy best practices:

• Need-to-Know Visibility - Contracts visible only to relevant parties
• No Global Observers - No admin parties that see all transactions
• Privacy-Preserving Compliance - Whitelist checks without leaking user lists
• Issuer-Centric Model - Issuer controls minting/burning on behalf of users (no user Canton keys required)
• Fingerprint-Based Authentication - EVM addresses map to Canton parties via cryptographic fingerprints

Documentation

Document	Description
CHANGELOG.md	Version history and migration guides
Architecture Proposal	Technical design and roadmap

License

Apache 2.0

Support

• Documentation: See docs/
• Issues: GitHub Issues

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