You need to convert your private certificate into a DER (Distinguished Encoding Rules) format.
The DER format, which is one of the formats for X.509 certificates, provides a platform-independent method of encoding certificates for transmission between devices and applications. For these instructions, it is assumed that the certificate to be converted is the eneCert.pem certificate that you created with the enecerts utility and stored in the %ENDECA_CONF%\etc directory.
openssl x509 -inform PEM -outform DER -in eneCert.pem -out eneCert.der
The eneCert.der certificate will be later used in the controller.aspx file.