Gpg4win (GNU Privacy Guard for Windows) is encryption software for files and emails.
What is Gpg4win?
Gpg4win enables users to securely transport emails and files with the help of encryption and digital signatures. Encryption protects the contents against an unwanted party reading it. Digital signatures make sure that it was not modified and comes from a specific sender.
Gpg4win supports both relevant cryptography standards, OpenPGP and S/MIME (X.509), and is the official GnuPG distribution for Windows. It is maintained by the developers of GnuPG. Gpg4win and the software included with Gpg4win are Free Software (Open Source; among other things free of charge for all commercial and non-commercial purposes).
Creation of Gpg4win was supported by the German Federal Office for Information Security (BSI).
Gpg4win is an installer for Windows and contains several Free Software components:
The backend; this is the actual encryption tool.
A certificate manager for OpenPGP and X.509 (S/MIME) and common crypto dialogs.
An alternative certificate manager for OpenPGP and X.509 (S/MIME).
A plugin for Microsoft Outlook 2003/2007/2010/2013/2016 (email encryption). With Outlook 2010 and higher GpgpOL supports MS Exchange Server.
A plugin for Microsoft Explorer (file encryption).
- Gpg4win Compendium
The documentation (for beginner and advanced users), available in English and German.
Gpg4win requires at least Windows XP (including Windows 10). Both 32 and 64bit systems are supported.
The Outlook plugin GpgOL is compatible with Microsoft Outlook 2003, 2007, 2010, 2013 and 2016 (both 32 and 64bit). GpgOL supports MS Exchange Server for Outlook 2010 and higher.
Aim of Gpg4win Initiative
The Gpg4win initiative aims to provide a current Gpg4win Windows installation package including the GnuPG encryption tool and associated applications. The documentation ("Gpg4win Compendium") is maintained as part of the effort.
Both OpenPGP and S/MIME should be supported in a unified way.
Gpg4win is an international effort. Due to the origins of the initiative there is a full German translation. Additional translators are welcome!
A main achievement of Gpg4win is to focus on the builder, which allows to easily create updated installers. The builder runs best on a GNU/Linux system. Almost all software components are automatically cross-compiled for integration into the installer. Thus Gpg4win does not depend on a single person to manually create the installer.
Short Study: Sustainable Free Software
Before Gpg4win2 was developed, Jan-Oliver Wagner and Bernhard Reiter wrote a short study about "Sustainable Free Software: From project to permanent activity, using the example Gpg4win".