openssl genrsa -out myCA.key 2048

This will create an rsa key file named myCA.key that we use to sign the public pem file generated next.

Create a pem file signed with the key:

openssl req -x509 -new -nodes -key myCA.key -sha256 -days 365 -out myCA.pem

This will prompt you to answer some questions to generate the pem file:

Country Name (2 letter code) [AU]:**JE**
State or Province Name (full name) [Some-State]:**Jersey**
Locality Name (eg, city) []:**St. Helier**
Organization Name (eg, company) [Internet Widgits Pty Ltd]:**ShareWiz**
Organizational Unit Name (eg, section) []:**IT**
Common Name (e.g. server FQDN or YOUR name) []:**sharewiz.net**
Email Address []:

At this point you should have 2 files:

myCA.pem
myCA.key

The myCA.pem file is the public key.