  A variety of Transparency-Enhancing Technologies has been presented during
the past years. However, investigation of frameworks for classification and
assessment of Transparency-Enhancing Technologies has lacked behind. The lack
of precise classification and categorization approaches poses an obstacle not
only to systematic requirements analysis for Transparency-Enhancing
Technologies but also to investigation and analysis of their capabilities and
their suitability to contribute to privacy protection. This paper addresses
this research gap. In particular, it presents a set of categorization
parameters for describing the properties and functionality of a
Transparency-Enhancing Technology on the one hand, and a categorization of
Transparency-Enhancing Technologies on the other hand.
