Create self-signed SSL Certificate

# generate private key
openssl genrsa -des3 -out server.pass.key 2048

# remove passphrase from Key
openssl rsa -in server.pass.key -out server.key
rm server.pass.key

# generate csr (certificate signing request)
openssl req -new -key server.key -out server.csr

# generate self-signed certificate
openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

Create Client Certifcate that can be used by Firefox and other Browsers

openssl pkcs12 -export -in client.crt -inkey client.key -out client.p12