OS2Forms Digital Signature server module

Module purpose

This module provides Digital signature server functionality for Digital Signature clients, implemented by this module: https://github.com/OS2Forms/os2forms/tree/develop/modules/os2forms_digital_signature

How does it work

This module is passively waiting for the requests on endpoint /sign. The request type is identified by the action argument. Supported operations:

• getcid: Retrieves a correlation ID (randon UUID)
• sign: Initiates a signing process for the specified URI, forward URL, and hash.
• cancel or result: Processes the result or cancels an operation using information from the specified file.
• download: Send the file for downloading, optionally retaining it based on the leave parameter.

Settings page

The module provides a configuration form at /admin/os2forms_dig_sig_server/settings The following settings are available:

• Signing server URL

  The base URL of the signing service. Example: https://signering.bellcom.dk

• Allowed domains

  A comma-separated list of allowed domains from which signing requests are accepted. Example: sign.localhost, sign.local, localhost, example.vhost.com

• Files working directory

  Directory where the source and signed PDF files will be stored. For security reasons, use private:// or a path outside the Drupal web root.

• Hash Salt used for signature

  Secret string used when generating and verifying hashes. Must match the hash salt configured on the signature client.

• Enable debug mode

  When enabled, debug messages about signing operations are logged to Drupal watchdog.

Nginx configuration

The installation implementing Digital Signature must have this canonical redirect for /sign.php

if ($request_uri ~* ^/sign\.php(?:\?|$)) {

    return 301 /sign?$args;

}