2015
HTTP Public Key Pinning (HPKP)
[Using HTTPS](https://www.bjornjohansen.com/securing-nginx-ssl) helps preventing someone from snooping your username/password or hijacking your sessions. [Using HSTS](https://www.bjornjohansen.com/optimizing-https-nginx) makes sure the connection stays on HTTPS, even if a MITM tries to redirect you to the plain HTTP version of a web site. But it is easier than you might think for a MITM to use a rogue certificate, making you believe everything is fine. HTTP Public Key Pinning (HPKP) helps the browser check that everything actually is fine.