Explains how to install and configure Apache with a mod_md module to secure traffic with Let's Encrypt free TLS/SSL certificate on Ubuntu 20.04 LTS Linux.

An easy-to-use secure configuration generator for web, database, and mail software

Let's say you want http://www.example.com/secure/ to always be sent over SSL (I presume here that both the normal and the SSL vhost have the same content). You could do this by linking to the correct page from within your HTML pages... but there will always be some user who will sneak by it that way.

NameVirtualHost *:80
<VirtualHost *:80>
   ServerName www.example.com
   Redirect permanent / https://secure.example.com/
</VirtualHost>

<VirtualHost _default_:443>
   ServerName secure.example.com
   DocumentRoot /usr/local/apache2/htdocs
   SSLEngine On
   # etc...
</VirtualHost>

You want to force people coming to your site to use HTTPS. Either for the entire site or a small sub-section of it.

RewriteEngine On
# This will enable the Rewrite capabilities

RewriteCond %{HTTPS} !=on
# This checks to make sure the connection is not already HTTPS

RewriteRule ^/?(.*) https://%{SERVER_NAME}/$1 [R,L]
# This rule will redirect users from their original location, to the same location but using HTTPS.
# i.e.  http://www.example.com/foo/ to https://www.example.com/foo/
# The leading slash is made optional so that this will work either in httpd.conf
# or .htaccess context

Le but de CAcert est par la sensibilisation et l'éducation de promouvoir la sécurité informatique au travers de la cryptographie, spécialement en mettant à disposition des certificats cryptographiques. Ces certificats peuvent être utilisés pour chiffrer des courriels et les signer électroniquement, authentifier et habiliter des utilisateurs se connectant sur des sites web ainsi que sécuriser la transmission de données sur internet. Toute application qui supporte le protocole « Secure Socket Layer » (SSL ou TLS) peut utiliser les certificats signés par CAcert, comme peut le faire toute application qui utilise des certificats X.509, par exemple pour du chiffrement, de la signature de code ou de la signature de documents.