This package contains libksba 1.0.2 from 

http://www.gnupg.org/(en)/related_software/libksba/index.html

Libksba is a library to make the tasks of working with X.509 certificates,
CMS data and related objects more easy. It provides a highlevel interface to
the implemented protocols and presents the data in a consistent way.

This lib is e.g. used by GnuPG 2 to provide support for S/MIME certificates.