GNU Libtasn1

Libtasn1 is the ASN.1 library used by GnuTLS, p11-kit and some other packages. It was originally written by Fabio Fiorina, and now maintained as a GNU package.

The goal of this implementation is to be highly portable, and only require an ANSI C99 platform.

For status information on what's happening with the package, see the NEWS file from live sources.

Libtasn1 is licensed under the GNU Lesser General Public License version 2.1 or later.

Downloading Libtasn1

Libtasn1 can be found on the main GNU ftp server: (via http) and (via ftp). It can also be found on one of the mirrors of; please use a mirror if possible.

Official releases are signed with one of the following keys:


The Libtasn1 manual is available online. Quick links to the most popular formats:

Mailing Lists

Everything related to Libtasn1 is discussed on the help-libtasn1 mailing list.

Announcements about Libtasn1 and most other GNU software are made on <>.


Report any issues at and questions on help-libtasn1 mailing list.


The goal is to provide a library of high quality. We use autoconf, automake, and libtool to achieve high portability and gnulib to support a platform independent coding style. The self-tests are run under a CI on gitlab.


The development of libtasn1 takes place on gitlab. For sources and other information, please see the Libtasn1 project page.

You can check out the sources by using git as follows:

$ git clone


Libtasn1 is currently being maintained by Simon Josefsson and Nikos Mavrogiannopoulos. Please use the issue tracker or the mailing lists above for contact.

Please remember that development of Libtasn1, and GNU in general, is a volunteer effort, and you also can contribute. For information, please read How to help GNU.