I didn't want to look up the openssl commands to create a CA and sign certificates again, so I've created this very simple script to make it easier.

Creates a certificate authority. The private key is stored unencrypted in ca.key.pem. The certificate you need to import into your browser is in ca.cert.pem.

Creates and signs a certificate for *.example.com using the CA created previously. The certificate and private key, which you need to give to your web server, are stored in _.example.com.cert.pem and _.example.com.key.pem respectively.

Creates a self-signed certificate for *.example.com, independent of any CA. The certificate and private key, which you need to give to your web server, are stored in _.example.com.cert.pem and _.example.com.key.pem respectively.