Openssl

openssl

https://www.digitalocean.com/community/tutorials/openssl-essentials-working-with-ssl-certificates-private-keys-and-csrs

in cd ../vhosts/somecerts/smallcerts/

Generate a Private Key and a CSR

openssl req -newkey rsa:512 -nodes -keyout domain.key -out domain.csr

Generate a Self-Signed Certificate from an Existing Private Key

openssl req -key domain.key -new -x509 -days 365 -out domain.crt