Trezor Bridge® — Safe Access to Your Hardware Wallet©

Overview of Trezor Bridge

Trezor Bridge® is the official communication intermediary that allows your computer or browser to safely interact with your Trezor hardware wallet. This trusted software enables seamless, encrypted exchanges between your host device and your hardware wallet, bridging the gap between web applications, local client software, and your secure device. It is developed to ensure that none of your private keys ever leave your Trezor device, safeguarding your digital assets from exposure.

With Trezor Bridge, users can transact, manage accounts, sign messages, and verify addresses inside their web interface or native wallet apps. The Bridge runs locally on your machine, eliminating reliance on third‑party servers for communication, thereby enhancing privacy and reducing attack surfaces.

Architecture & Workflow

How Bridge Works

The architecture of Trezor Bridge is built around a local HTTP interface, enabling the host to send commands to the Trezor device over USB or WebUSB. When a wallet app requests to connect, it communicates via this local bridge to forward commands (e.g. “get address,” “sign transaction”) to the hardware device.

Components & Roles

Bridge Core

The core module listens on a dedicated local port (often 21325) and accepts JSON‑RPC style requests. It validates the incoming request origin, checks permissions, and forwards allowed commands to the Trezor device using a secure hardware link.

Web Integration Layer

On the browser side, WebUSB or WebHID interfaces may be used, depending on browser support. This layer wraps device-level calls into asynchronous promises, handling errors, user prompts (e.g. “allow device access”), and fallback logic.

Native App Compatibility

Some desktop applications bypass the web interface and access the Bridge directly. They invoke the same local HTTP interface but embed it within their own GUI framework for a streamlined user experience.

Security & Trust Paradigm

End‑to‑End Assurance

Trezor Bridge is designed so that all cryptographic key generation, signing, and private data remains strictly inside the hardware wallet. Bridge only handles transport of encrypted commands and responses. If an attacker tried to intercept this layer, they would see only ciphertext, not raw keys or sensitive material.

Permission Control

Before any connection is allowed, Bridge prompts the user to approve access. You can configure persistent permissions or revoke individual WebUSB origins. This control ensures that unauthorized websites cannot silently access your device.

Integrity & Updates

Trezor Bridge is digitally signed and validated during installation and updates. It auto‑updates to patch bugs, vulnerabilities, and compatibility issues. The update process verifies signatures before applying new binaries, protecting from malicious tampering.

Defending Against Common Threats

Because Bridge operates locally (not over the internet), it mitigates many network-based attacks such as man‑in‑the‑middle or remote proxies. Combined with the hardware wallet’s secure enclave and user confirmations on the device, the system greatly reduces phishing or remote intrusion risks.

Installation & Usage Guide

Supported Platforms

Trezor Bridge supports Windows, macOS, and Linux. Each platform has a native installer or package (e.g. .exe, .dmg, .AppImage). After installation, Bridge runs in the background and begins listening for wallet connections.

Step‑by‑Step Setup

Download the official Bridge installer from trezor.io (verify checksums).
Run the installer and allow required permissions (USB access, local network).
Once installed, connect your Trezor hardware wallet to your computer.
Open your wallet app or web interface; it should detect Bridge automatically.
Approve device access to the WebUSB origin when prompted.
Begin interacting with your wallet to view balances, send funds, or sign messages.

Troubleshooting Common Issues

If your browser or wallet app cannot locate the device:

Make sure Bridge is running (check system tray or processes).
Ensure no firewall or security software is blocking local ports.
Try a different USB cable or port (avoid USB hubs).
Ensure your browser supports WebUSB or the appropriate interface.
Reinstall Bridge or reboot your system.

Frequently Asked Questions (FAQ)

1. What exactly is Trezor Bridge and why is it needed?: Trezor Bridge is local client software that mediates communication between the host (browser or wallet app) and the Trezor hardware wallet. It is needed because browsers alone cannot reliably or securely talk to USB devices in all environments, so Bridge acts as a safe “bridge.”
2. Does Bridge ever see my private keys?: No. Bridge only handles encrypted messages and commands. All private key operations (generation, signing) happen inside the Trezor hardware device. Bridge never has access to raw private key material.
3. Is it safe to auto‑update Bridge?: Yes, if you downloaded Bridge from the official source. Updates are digitally signed. The update mechanism verifies signature integrity before installing, so malicious versions cannot silently replace the legitimate Bridge.
4. Can I use Bridge on multiple devices at once?: Yes, you can install Bridge on several computers (e.g. desktop, laptop). Each instance will run locally, but the permissions and configuration are per machine. You may need to approve device access on each separately.
5. What should I do if Bridge fails to detect my Trezor device?: First, check that Bridge is running (check system tray or process list). Then try reconnecting the USB cable or using a different port. Disable firewall or security apps that might block local ports. If problems persist, reinstall Bridge from the official site and reboot your system.