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GPG smart card daemon (SCD)

DigiCert​​®​​ Software Trust Manager GPG Smart Card Daemon (SCD) is a GPG compliant SCD client-side tool that integrates with the GPG-agent (part of the GPG tool suite) for all GPG based hash signing use cases.

The GPG SCD handles secure key generation, application hash signing, and associated certificate-related requirements when the signing request does not require the transportation of files and intellectual property.

What signing tools can GPG SCD integrate with?

Use the DigiCert​​®​​ Software Trust Manager GPG SCD to sign files with GPG keys using a hash-based approach while maintaining key protection, permission-based access and reporting all signing activities:

  • GPG

  • Debian package (DEB)

  • Git commit

  • Redhat Package Manager (RPM)

  • Redhat container image

What can the GPG SCD sign?

DigiCert​​®​​ Software Trust Manager GPG SCD enables secure hash-based signing of any type of file, including:

  • Executables

  • Installers

  • Files

  • Applications

  • Drivers

  • Images

  • Scripts

Download GPG Smart Card Daemon (SCD)

  1. In the Software Trust menu, go to Resources > Client tool repository.

  2. Select the Client tools tab.

  3. Select your operating system.

  4. Click the download icon next to GPG Smart Card Daemon (SCD).

  5. Move the GPG SCD client (ssm-scd) to the location of your choice.

Configuration file

A configuration is required to use the GPG SCD client. The following parameters can be used in the config file.

Parameter

Description

scdaemon-program

Point this parameter to DigiCert​​®​​ Software Trust Manager GPG Smart Card Deamon Client (ssm-scd).

Command:

scdaemon-program /home/<username>/ssm-scd

verbose

An optional parameter that enables extra verbose logging by gpg-agent.

Command:

verbose

debug-all

An optional parameter that enables more in-depth debug logging by gpg-agent.

Command:

debug-all

log-file /home/someuser/.gnupg/gpg-agent.log

An optional parameter that writes logs in a specified file.

Command:

log-file /home/<username>/.gnupg/gpg-agent.log

pinentry-program

An optional parameter that points to pinentry program (a small collection of dialog programs that allow GnuPG to read passphrases and PIN numbers in a secure manner), this comes with GPG installer in most of the cases.

Command:

pinentry-program /<username>/bin/pinentry

Create a GPG configuration file

To create a GPG configuration file:

  1. Open an integrated development environment (IDE) or plain text editor.

  2. Copy the following text into the file:

    verbose 
    debug-all 
    log-file <log_file_path_for_gpg_agent> 
    scdaemon-program <path_of_the_scd_ssm> 
    pinentry-program <path_of_pinentry_installed_as_part_of_gpg> 
  3. Save the file as gpg-agent.conf.

  4. Store the file in the following location based on your operating system: