Enabling SSL in Jenkins is a bit tricky. To do this first you need to convert your keys to PKCS12.
$ sudo openssl pkcs12 -inkey key.pem -in cert.pem -export -out keys.pkcs12
Then created a keystore (password for keystore should be same as password for key).
$ sudo keytool -importkeystore -srckeystore keys.pkcs12 -srcstoretype pkcs12 -destkeystore keystore