Architecture

This document outlines Pontis core functionality, network integration, and key operational details.

Pontis Bridge is designed to securely bridge assets across the Bitcoin, Stacks, and EVM-based networks. Built with robust safety mechanisms, it supports:

• Automatic and manual emergency procedures.

• Integration with key networks to handle Runes, Ordinals, and BTC.

• Consistent, reliable service for cross-chain transactions.

Bridge Parameters

Signer Nodes

• Role of Signer Nodes:

  • Validate transactions independently to ensure integrity.

  • Prevent transaction approval if any validation check fails.

  • Switch listeners in case of malicious behavior from the primary listener.

• Asigna Multisig SDK:

  • Implements the logic for secure and decentralized transaction signing.

• Listener Node Responsibilities:

  • Monitor the source networks (Bitcoin, Stacks, EVM).

  • Determine the correct signer nodes (BTC, STX, EVM) for finalizing transactions on the target chain.

Fees

• Fee Collection:

  • Collected for each bridging transaction and transferred to the Pontis treasury.

Supported Networks

Network	Supported Assets
Bitcoin	BTC, Runes, BRC-20, Ordinals
Stacks	BTC, Runes, BRC-20, Ordinals
EVM Chains	BTC, Runes, BRC-20, TBA

Emergency Handling

In emergencies (e.g., unsupported assets, node migration):

1. Manual Intervention Required:

   • Listener nodes are halted to avoid conflicts.

   • Signer nodes manually verify and approve transactions via terminal.

2. Process:

   • Transactions are verified, signed, and confirmed manually.

   • The listener resumes operation once the process is complete.

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Transaction Acceleration

• When a transaction is stuck:

  • Acceleration becomes available after a specified number of blocks (varies by chain).

  • Signer nodes validate the gas adjustment and ensure transaction details remain unchanged before approval.

User Flow

• Users initiate only one transaction to complete the bridging process.

Fee Configuration

• Managed Separately:

  • Fees are controlled independently of the main multisig.

  • Pontis enforces safeguards to prevent malicious fee configurations.

Multisig Control of Signer Nodes

• Multisig Governance:

  • The main multisig governs the controller contract, responsible for:

    • Setting the current bridge instance.

    • Managing mint and burn operations for Fungible Tokens and Non-Fungible Token contracts.

Transaction Uniqueness Transaction uniqueness is ensured through the tx-hash-and-vout parameter:

Network	Uniqueness Parameter
BTC	tx hash + UTXO number
Runes (on BTC)	tx hash + UTXO number + rune number in UTXO
Other Networks	tx hash

• Key UTXO is required for bridging assets from any network to Bitcoin, ensuring transaction uniqueness even if the main listener restarts.

Ordinals Bridge

• Marketplace Integration:

  • Separate contracts exist for each Ordinals collection.

  • These contracts will support future marketplace functionalities.

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Confirmation Counting

Network	Confirmation Requirement
Bitcoin	1 Bitcoin block confirmation
Stacks	1 Bitcoin block confirmation
EVM Networks	Configurable per network

Smart Contracts

Contract Name	Functionality
pontis-bridge-controller.clar	Manages ownership migration and multisig updates.
pontis-bridge-fee-manager.clar	Handles fee configuration for the bridge.
pontis-bridge-v1.clar	Primary bridging contract; only authorized multisig signers can finalize actions.
pontis-ordinals-nft.clar	Sample contract for bridging Ordinals collections.
pontis-bridge-ft.clar	Sample fungible token contract for psBTC and Runes.

External API Integrations

The Pontis Bridge leverages industry-leading external APIs to ensure consistent network communication and minimize downtime:

• Unisat API

• Hiro API

• Blockstream API

• Quicknode