Signbridge

SignBridge is a browser extension that implements the Generic Web HSM Signing Protocol, enabling web applications to securely sign PDF documents using hardware security modules (HSM), smartcards, and USB tokens via the PKCS#11 standard.

Here you can download the native host:
https://github.com/ASE-Bucure-ti/SignBridge

Here you can test different web flows scenarios:
https://signbridge.ase.ro

How it works:
SignBridge acts as a bridge between web applications and a lightweight native host application installed on your computer. When a web app requests a document signature, the extension relays the request to the native host, which interfaces with your PKCS#11-compatible hardware (e.g., SafeNet eToken, Gemalto, YubiKey, or any PKCS#11 device) to perform the cryptographic signing operation locally. Private keys never leave your hardware device.

Key features:
• Standards-based — implements the open Generic Web HSM Signing Protocol v1.0 developed internally
• Works with any PKCS#11-compatible hardware token, smartcard, or HSM
• Supports single and batch PDF signing workflows
• Visible and invisible digital signatures with customizable appearance
• PAdES B-B and B-T signature profiles with optional timestamping
• All cryptographic operations happen locally — private keys never leave the hardware device
• No user data is collected, transmitted, or stored by the extension

Requirements:
• The SignBridge native host application must be installed on your computer
• A PKCS#11-compatible hardware device (smartcard, USB token, or HSM) with its vendor drivers installed

For developers:
SignBridge is designed for seamless integration. Web applications communicate with the extension via standard DOM events (postMessage). A lightweight JavaScript SDK is available for easy integration into any web application. Visit the project documentation for the protocol specification and integration guide.

Privacy:
This extension does not collect, store, or transmit any personal data. It only relays signing requests between the web page and the locally installed native host application. All cryptographic operations are performed entirely on your local machine.