For contact tracing apps aiming to support society to deal with the current SARS-CoV-2 / Covid-19 pandemic, we only endorse privacy respecting designs that collect and use data in a decentralized manner, in line with our general approach to decentralizing digital identity in project Digidow, opens an external URL in a new window. Centralized approaches to managing (pseudo-) identities and matching contact data pose too great a risk of becoming tools of mass surveillance and control far beyond dealing with the current crisis. Therefore, we fully support the Joint Statement on Contact Tracing, opens an external URL in a new window and the approaches, protocols, and prototype implementations listed in it.