1. create the certificate and private key using openssl

$ openssl req -nodes -text -x509 -newkey rsa:2048 -keyout secret.pem -out certificate.pem -days 356

2. Upload the certificate.pem in Adobe IO Console-> Your Integration-> Public keys

3. convert private key to DER format

$ openssl pkcs8 -topk8 -inform PEM -outform DER -in secret.pem -nocrypt > secret.key

4. Edit the config.properties in src/main/resources/ and add the values from your Adobe Developer Console integration.