diff --git a/certificates.go b/certificates.go
index 233f25d30..23354972e 100644
--- a/certificates.go
+++ b/certificates.go
@@ -125,6 +125,7 @@ func generateSingleCertificate(isCa bool) (*x509.Certificate, error) {
 	if isCa {
 		template.IsCA = true
 		template.KeyUsage |= x509.KeyUsageCertSign
+		template.Subject.CommonName = "Arduino"
 	}
 
 	return &template, nil
@@ -138,7 +139,7 @@ func generateCertificates() {
 	os.Remove("key.pem")
 
 	// Create the key for the certification authority
-	caKey, err := generateKey("")
+	caKey, err := generateKey("P256")
 	if err != nil {
 		log.Error(err.Error())
 		os.Exit(1)
@@ -176,7 +177,7 @@ func generateCertificates() {
 	log.Print("written ca.cert.cer")
 
 	// Create the key for the final certificate
-	key, err := generateKey("")
+	key, err := generateKey("P256")
 	if err != nil {
 		log.Error(err.Error())
 		os.Exit(1)
@@ -209,4 +210,8 @@ func generateCertificates() {
 	pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
 	certOut.Close()
 	log.Print("written cert.pem")
+
+	ioutil.WriteFile("cert.cer", derBytes, 0644)
+	log.Print("written cert.cer")
+
 }