diff --git a/docs/configure_https.md b/docs/configure_https.md
index 9281d8125..0c3641066 100644
--- a/docs/configure_https.md
+++ b/docs/configure_https.md
@@ -27,26 +27,18 @@ Otherwise, if you use IP address to connect your registry host, CN can be anythi
 ```
 3) Generate the certificate of your registry host:
 
-On Ubuntu, the config file of openssl locates at **/etc/ssl/openssl.cnf**. Refer to openssl document for more information. The default CA directory of openssl is called demoCA. Let's create necessary directories and files:
-
-```
-  mkdir demoCA
-  cd demoCA
-  touch index.txt
-  echo '01' > serial
-  cd ..
-```
 If you're using FQDN like **reg.yourdomain.com** to connect your registry host, then run this command to generate the certificate of your registry host:
 
 ```
-  openssl ca -in yourdomain.com.csr -out yourdomain.com.crt -cert ca.crt -keyfile ca.key -outdir .
+  openssl x509 -req -days 365 -in yourdomain.com.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out yourdomain.com.crt
 ```
 If you're using **IP**, say **192.168.1.101** to connect your registry host, you may instead run the command below:
 
 ```
   echo subjectAltName = IP:192.168.1.101 > extfile.cnf
 
-  openssl ca -in yourdomain.com.csr -out yourdomain.com.crt -cert ca.crt -keyfile ca.key -extfile extfile.cnf -outdir .
+  openssl x509 -req -days 365 -in yourdomain.com.csr -CA ca.crt -CAkey ca.key -CAcreateserial -extfile extfile.cnf -out yourdomain.com
+.crt
 ```
 ##Configuration and Installation
 After obtaining the **yourdomain.com.crt** and **yourdomain.com.key** files, 
@@ -124,3 +116,4 @@ If you've mapped nginx 443 port to another, you need to add the port to login, l
     update-ca-trust
     ```
     
+