Generate Self-Signed SSL certificate using OpenSSL in one line

Published October 16, 2022

As a web developer or website owner, you may sometimes need to create self-signed SSL certificates to make your web applications run. Generating self-signed certificates is an easy process. In fact, you can do it in one step.

Self-signed SSL certificate

We will use SHA256 with RSA 2048 encryption. The certificate will be valid for 1 year.

Generate SSL certificate and key

To generate the certificate and key, run this:

openssl req -new -newkey rsa:2048 -sha256 -days 365 -nodes -x509 -keyout server.key -out server.crt

If you want to include your name or your company name, run this:

openssl req -subj '/ John/C=US' -new -newkey rsa:2048 -sha256 -days 365 -nodes -x509 -keyout server.key -out server.crt

Configure web server

Now, you have the certificate server.crt and key server.key. Copy them to a new directory ssl under the web server root directory.

If you use Nginx, here's a sample nginx.conf block:

server {
    listen      443 ssl;
    server_name localhost;
    root   html;

    ssl on;
    ssl_certificate     /etc/nginx/ssl/server.crt;
    ssl_certificate_key /etc/nginx/ssl/server.key;
    ssl_protocols TLSv1.3;

If you use Apache web server, here's a sample apache2.conf (or httpd.conf):

    DocumentRoot html
    ServerName localhost
    SSLEngine on
    SSLCertificateFile /etc/apache2/ssl/server.crt
    SSLCertificateKeyFile /etc/apache2/ssl/server.key

Disable https warning from Chrome

When you navigate to https://localhost, on some browsers like Chrome, you get this Not Secure warning. You can disable it in Chrome by following these steps:

1) Open Chrome and enter this in the address bar


You will see this on the top:

Allow invalid certificates for resources loaded from localhost. Mac, Windows, Linux, Chrome OS, Android
Allows requests to localhost over HTTPS even when an invalid certificate is presented. #allow-insecure-localhost

2) Then, enter this in the address bar


Enter localhost in the Domain field.

Restart Chrome and go back to https://localhost. Hopefully, it should not show the No Secure warning.

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Last Updated: October 16, 2022.     This post was originally written on April 05, 2015.