SSL

SSL: secure sockets layer

Protocols for establishing authenticated and encrypted links between networked computers.

The protocol is deprecated in 1999 with TLS release, but still used to refer to this technique.

TLS: transport layer security

Successor of SSL.

HTTPS

Tunnel HTTP over TSL/SSL which encrypts the HTTP payload.

You need to buy certificates.

Or use free license by acme.sh !

acme.sh

https://github.com/acmesh-official/acme.sh/wiki/%E8%AF%B4%E6%98%8E

curl  https://get.acme.sh | sh
alias acme.sh=~/.acme.sh/acme.sh

# setup auto upgrade
acme.sh --upgrade --auto-upgrade

# setup http for nginx (i.e, the website can be accessed by http), so acme.sh can verify your identity.
# server {listen 80; ...} 

# issue a license for nginx
# -d must be in nginx config (`server_name www.kiui.moe;`)
# Some times it reports `can't get nonce` or looping `sleep 10 and retry`, just re-run the code several times :)
# Other times it reports processing --> timeout, just try later.
acme.sh --issue -d www.kiui.moe --nginx # --debug 2

# install cert
acme.sh --install-cert \
        -d www.kiui.moe \
        --key-file /etc/nginx/key.pem  \
        --fullchain-file /etc/nginx/cert.pem \
        --reloadcmd "systemctl restart nginx"

# setup https for nginx. (in manual)
# server {listen 443 ssl; ...}

# manual renew all certs
acme.sh --cron --force # --debug 2