1. Generate certificate and private key pair openssl req -nodes -new -x509 -keyout kumar_key.pem -out kumar_cert.pem 2. Convert the certificate kumar_cert.pem to der format openssl x509 -inform PEM -outform DER -in kumar_cert.pem -out kumar_cert.der 3. Move the DER encoded certificate to the USERS_PKI directory cp kumar_cert.der ~/.prosysopc/prosys-opc-ua-simulation-server/USERS_PKI/CA/certs/ 4. Restart the Prosys OPC UA Simulation server 5. Within UaExpert, use the following settings: Certificate: DER encoded certificate - kumar_cert.der Private Key: private-key file (without passphrase) - kumar_key.pem