How to create a self-signed certificate ?

Private key generation:

openssl genrsa -out ./server.key 1024

Public key (certificate) generation:

openssl req -new -key ./server.key -x509 -days 3650 -out ./server.crt

(3650 means ten years of validity)

View the certificate content (human read):

openssl x509 -in server.crt -text -noout

Then you can use this certificat for example in your apache serveur to handle HTTPS urls :

    SSLEngine On
    SSLCertificateFile    /etc/apache2/ssl/server.crt
    SSLCertificateKeyFile /etc/apache2/ssl/server.key