If you check the encryption box, the communication between browser and WeeChat will be encrypted.
Note: Due to a
bug encryption will not work in Firefox. Unless you are using a certificate trusted by your browser, you must also first visit the URL https://weechathost:relayport/ to accept the certificate.
If you want to use an encrypted session you first have to set up the relay using SSL. It is easiest to use a self-signed certificate, which you can create like this:
$ mkdir -p ~/.weechat/ssl
$ cd ~/.weechat/ssl
$ openssl req -nodes -newkey rsa:2048 -keyout relay.pem -x509 -days 365 -out relay.pem
If WeeChat is already running, you can reload the certificate and private key with these commands:
/relay sslcertkey
/relay add ssl.weechat 8000