HPKP Supercookie

1. Pick a domain to use for the supercookie server, e.g. cyph.wang.

2. Point *.cyph.wang at a server running Ubuntu 16.04.

3. Run backend.sh cyph.wang ${domainWhitelist} on the server, with domainWhitelist being a whitespace-separated list of root domains approved to access this supercookie server.

4. Include hpkp-supercookie.js in your web frontend code.

5. const userData /* {id: number; isNewUser: boolean;} */ = await HPKPSupercookie('cyph.wang');

6. Track individual users between different sites and in incognito mode.

7. ???

8. PROFIT!