“Privacy enhancing technology” is a new concept, but not a new invention. Throughout history conceptual, legal and societal challenges to the private sphere of people have always inspired innovative inventions.

The 18th 19th Century “bathing machine” is an example as such. They were large wooden carts rolled into sea to protect particularly bathing women from the public gaze. More clumpsy and intrusive than modern day communication Anonymizers, but nevertheless  mobile privacy enhancing technologies aimed at protecting the private from the public.  The Hush-A-Phone from the 1920’s is another. Probably one of the first devices created to enhance the privacy of everyday tele communication, the Hush-A-Phone was a tube like device that one could apply to the telephone to protect the sound of one’s private conversations from outside listeners.

Privacy enhancing technologies have always existed. But gradually these inventions have adapted to a more complex public reality where social contexts and roles intervene and interrelate with the private sphere of people and today there is a particular momentum for inventive engineering in privacy as there is an increasing demand for more complex privacy solutions. Early computer cryptographers made a clear distinction between a private sphere that urgently needed protection from a clear cut public sphere, while many of today’s privacy enhancing technologies have been developed from a more nuanced view of the public and private spheres providing users with control over personal data, choice of anonymity, facilitating their use of legal rights etc.  A human approach to the open computer networks calls for more differential privacy solutions that places control in the hands of people and differentiate between various societal aims and social contexts.