  Given a query result of a big database, why-provenance can be used to
calculate the necessary part of this database, consisting of so-called
witnesses. If this database consists of personal data, privacy protection has
to prevent the publication of these witnesses. This implies a natural conflict
of interest between publishing original data (provenance) and protecting these
data (privacy).
  In this paper, privacy goes beyond the concept of personal data protection.
The paper gives an extended definition of privacy as intellectual property
protection. If the provenance information is not sufficient to reconstruct a
query result, additional data such as witnesses or provenance polynomials have
to be published to guarantee traceability. Nevertheless, publishing this
provenance information might be a problem if (significantly) more tuples than
necessary can be derived from the original database. At this point, it is
already possible to violate privacy policies, provided that quasi identifiers
are included in this provenance information. With this poster, we point out
fundamental problems and discuss first proposals for solutions.
