Configuring Piwik so that all requests are made over SSL (https://) is an easy way to improve security and keep your data safer. To ensure that logins, passwords and the token_auth are not sent in the clear, you can manually set a config file setting.
First of all, make sure that your Piwik server is configured so that requests to https://yourserver.com/piwik/index.php work as expected. We also recommend you use a valid SSL certificate. If you use NGINX web server, you likely need to add the following line to your nginx config:
fastcgi_param HTTPS $https if_not_empty;.
Or alternatively, you can also edit your config/config.ini.php file, and add the following under the [General] section, set the following:
[General] force_ssl = 1
Piwik will then automatically redirect all http:// requests to route to the https:// equivalent. Learn more tips about how to secure Piwik.