Nginx HTTP Server - Fourth Edition

Obtaining your SSL certificate

In order to generate your certificate, we'll need to provide Let's Encrypt with a few pieces of information, the first of which is a private encryption key that must be kept as safe as possible (any attacker that gets hold of this key would theoretically be able to impersonate your server). This key will be generated with a program called openssl, which must be installed on your system. Install it with the following command:

# apt-get install openssl

Alternatively, for Red Hat-based operating systems:

# yum install openssl 

Run the following command to generate your 2048-bit RSA private key, replacing example.com with your actual domain name:

# openssl genrsa -out example.com.key 2048 

A file called example.com.key ...