As security organisations go - probably one of the least recognised for their contribution to securing the web is letsencrypt.org Used by every household name on the internet, it promotes secure web connections by making available TLS certificates as a not for profit organisation.

Indeed many large and small businesses are heavy users of Letsencrypt and can fulfill certificate requirements where a formal certificate may not be absolutely mandatory.

It has a very versatile certificate management tool - certbot which gracefully handles installation and updates of certificates. Depending on your environment it can update your web server configuration with parameters required. It does require the appropriate server block to be defined but it can automatically configure the server block to reflect your SSL/TLS configuration.

A good example can be found at - https://www.nginx.com/blog/using-free-ssltls-certificates-from-lets-encrypt-with-nginx/ For other configurations visit - https://letsencrypt.org