GNU Generic Security Service - Libgss


This page contain information about Generic Security Service (GSS), a free implementation of RFC 2743/2744.

If you do not know what GSS is, I suggest to read the following resources.

Table of Contents

Documentation and Status

Refer to the GSS Manual web page for links to the manual in all formats; however, quick links to the most popular formats:

GSS has received some real-world testing and should be considered beta quality.

The source code framework is in place, an outline of the documentation is ready, and there are some simple self tests. The Kerberos 5 mechanism (RFC 1964 and RFC 4121) supports mutual authentication, channel bindings and the standard DES cipher. The non-standard 3DES cipher is also implemented, but unfortunately there are no specifications for AES. GNU SASL can use GSS to connect to GNU Mailutils and Cyrus IMAP servers that use the GSS implementations from MIT Kerberos or Heimdal. GNU MailUtils can also use GSS to serve GSSAPI clients. A SSH client and server with GSS authentication is provided by LSH with some patches.

GSS uses GNU Shishi to implement the Kerberos V5 mechanism.

Projects using GSS include:



A mailing list where GSS users may help each other exists, and you can reach it by sending e-mail to Archives of the mailing list discussions, and an interface to manage subscriptions, is available through the World Wide Web at


The releases are distributed from

The latest release is signed with OpenPGP key with fingerprint F8C4 D73C F638 C53C 06BE. Earlier releases were signed with an OpenPGP key with fingerprint B565716F or OpenPGP key with fingerprint 5A33 0664 A769 5426 5E8C.


There is a Savannah GSS project page. You can check out the sources by using git as follows:

git clone

The online git interface is available.

See the file README-alpha on how to bootstrap and build the package from version controlled sources.

We publish cyclomatic code complexity charts, self-test code coverage charts, and Clang code analysis