Encrypted contact information would be logged by a club upon entry, then automatically deleted 30 days later.
The website is a response to the Berlin Senate's regulations about contract-tracing and sharing—a system that allows venues to share the contact information of attendees in case of exposure to coronavirus.
closecontact aims to address privacy concerns by creating a "pass" with encrypted contact information that would be scanned upon entry to the club. The venue saves the encrypted information for 30 days, after which it is automatically deleted. If information is requested by health authorities within those 30 days, the club can decrypt the contact information and send it, but only for certain specified dates and times. (The app website offers a more detailed run-down of privacy features.)
The system was created by former and current employees of SoundCloud, Ableton, Beatport, Live Nation and Defected.
For more information, and the web app itself, check out the closecontact website.