Let's Encrypt is an automated, open certificate authority that offers free TLS/SSL certificates for public benefit. The service is provided by the Internet Security Research Group (ISRG). You can generate a wildcard SSL certificate to secure unlimited subdomains that belong to the same domain name. For example, a wildcard SSL certificate generated for **example.com** can secure **www**.example.com, **app**.example.com, **test**.example.com, and so on. This article demonstrates the steps to insta......