Trézór Bridge®™

Executive summary

Trézór Bridge®™ is a lightweight, local application that provides a secure, consistent, and auditable connectivity layer between hardware wallets and web-based applications. Modern browsers intentionally limit direct hardware access for security and compatibility reasons; Bridge resolves these gaps by running on the user's machine, handling USB/HID interactions with the device, and exposing an origin-restricted local API to trusted web pages. Crucially, Trézór Bridge does not alter the device-centric security model: private keys remain on the hardware device, and all signing requires explicit, physical confirmation by the user on-device.

Why a local bridge?

Browsers sandbox content and restrict low-level hardware interfaces (USB, HID) — which is good for security but makes hardware wallet connectivity inconsistent across platforms. A local bridge provides a stable, cross-platform layer that standardizes communication, centralizes driver handling and updates, and gives web developers a predictable API surface. It allows web wallets and dapps to offer rich, device-backed workflows without forcing users to install bespoke drivers per site or use non-standard browser features.

Core capabilities

• Cross-platform USB/HID handling: Reliable device detection and management for Windows, macOS, and Linux.
• Origin-scoped local API: Strict origin checks ensure only explicitly authorized web pages can talk to Bridge.
• Multiple device support: Route requests to the correct device instance when more than one hardware wallet is connected.
• Signed firmware & updates: Facilitates verified firmware updates via signed artifacts and fingerprint checks.
• Developer tooling: Debugging flags, CLI status endpoints, and official SDKs for building integrations.

Security model — preserving device-centric guarantees

Trézór Bridge acts as an intermediary but does not change the guaranteed placement of private keys. The security model relies on multiple layers:

• Hardware device: Seed generation, key derivation, and signature creation all occur on-device.
• Bridge: Handles local hardware APIs and enforces origin permissions; it does not have access to secrets.
• Browser/web app: Requests operations via the Bridge API; users must explicitly authorize connection and actions.
• User: Final arbiter — the device displays transaction data and requires physical confirmation before signing.

Primary rule: always verify transaction details on the physical device. The device display is the singlemost reliable source of truth when signing.

Installation & verification

Only download Trézór Bridge from official distribution channels. Follow platform-specific instructions and verify installer checksums or digital signatures when available. Typical steps include:

1. Download the installer from the official site (or package repository for Linux).
2. Run the installer with admin privileges where required — the installer registers a local service or background process to listen on the loopback interface.
3. Open a trusted web application that supports the device; when the web page requests access, Bridge will surface a permission dialog. Grant only to known, trusted origins.

Practical example: how a signing request flows

1. Web app constructs an unsigned transaction proposal and calls the Bridge API for signing.
2. Bridge verifies the web origin is allowed and forwards the unsigned payload to the connected device over USB/HID.
3. The hardware device parses the payload and shows the user the fully human-readable contents (addresses, amounts, fees, contract details where possible).
4. The user physically confirms on the device; the device returns a signature to Bridge.
5. Bridge returns the signed payload to the web app for broadcast to the network.

Developer integration — illustrative snippet

Developers should use official SDKs (for example, a library analogous to "Trezor Connect") rather than calling low-level endpoints directly. The snippet below is an illustrative pattern — consult the official SDK docs for production usage.

// Illustrative JavaScript (conceptual)
import TrezorConnect from 'trezor-connect';

async function init() {
  await TrezorConnect.init({ manifest: { email: 'dev@yourapp.example', appUrl: 'https://app.example' }});
}

async function getAddress() {
  const res = await TrezorConnect.getAddress({ path: \"m/44'/0'/0'/0/0\", coin: 'BTC' });
  if (res.success) {
    console.log('Address:', res.payload.address);
  } else {
    console.error('Error:', res.payload.error);
  }
}

Troubleshooting common scenarios

• Bridge not running: Confirm the Bridge background service/process is active. Restart the service and the browser.
• Permission denied: Revoke and re-grant origin permissions. Some browsers cache permission decisions — clearing site data can help.
• Device not detected: Try a different USB cable/port, ensure the device is unlocked, and check for conflicting drivers or software claiming the USB interface.
• Firmware update failure: Do not power off the device during an update. If interrupted, follow official recovery instructions and contact support.

Privacy & telemetry

Bridge runs locally and does not ship your private keys anywhere. However, connected web applications may interact with external block explorers or third-party services and that can leak metadata (addresses, txids, IP interactions). Review privacy policies of web apps you use and consider network protections (VPNs, Tor where appropriate) if you need enhanced privacy. Local logs may include device metadata; keep logs private and redact before sharing during troubleshooting.

Enterprise & automation guidance

For organizations, treat Bridge and the host machine as part of the security boundary. Recommended practices:

• Deploy Bridge on hardened hosts with restricted network access and automated deployment tooling.
• Use role-based access controls to define who can approve device connections and who can broadcast signed transactions.
• Prefer multisig and HSM-backed signing for high-value custody rather than single-device signing wherever possible.
• Log activity for audits but redact sensitive fields and protect audit logs with strong access controls.

CLI & diagnostics — examples

# Illustrative commands (replace with vendor-provided tooling)
trezor-bridge --status         # show running status
trezor-bridge --log-level debug # start with verbose logs for troubleshooting
trezor-bridge --reinstall      # repair or reinstall (platform dependent)

Compatibility matrix

Legal & trademark note

Trézór and Trézór Bridge are product trademarks. This document is informational and not legal advice. When redistributing, respect licensing and trademark rules provided by the vendor and consult legal counsel for commercial usage questions.

Conclusion

Trézór Bridge®™ fills a critical role in secure crypto ecosystems: enabling reliable, convenient web workflows while preserving the core security guarantees of hardware wallets. It provides a cross-platform, origin-aware local API, robust developer tooling, and troubleshooting primitives to make web-based signing practical and safe. Always install from official channels, verify installers and firmware where possible, restrict origin permissions to trusted sites, and rely on on-device verification as the primary defense against unauthorized signing.

Quick checklist: Download from official site • Verify checksums/signatures • Allow only trusted origins • Confirm all details on-device • Keep Bridge & firmware updated.