What is the Difference Between Self-Managed vs Public SSL/TLS Certificates? 🚀

DevOps Engineers often work with TLS certificates, and understanding the difference between self-managed and paid certificates is very important.

So lets understand the basics.

𝗪𝗵𝗮𝘁 𝗶𝘀 𝗮 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗲 𝗔𝘂𝘁𝗵𝗼𝗿𝗶𝘁𝘆?

Certificate Authority (CA) is usually a company or organization that issues digital certificates.

Here's how to request a TLS certificate from a well-known Certificate Authority (CA) like Verisign, LetsEncrypt or Comodo:

- Create a Certificate Signing Request (CSR) with a private key. The CSR includes details about your location, organization, and FQDN (Fully Qualified Domain Name).

- Send the CSR to the trusted CA.

- The CA validates the request and sends back a TLS certificate signed using the CA’s private key.

- Validate and use this TLS certificate with your applications.

Most browsers and operating systems 𝘀𝘁𝗼𝗿𝗲 𝗿𝗼𝗼𝘁 𝗖𝗔 𝗰𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗲𝘀 from all the trusted CAs.  You can view them from the browser settings.

That is why browsers don’t show security messages when visiting websites using TLS from a trusted and well-known commercial CA.

Each browser has its own set of criteria and processes for accepting and trusting CAs.

𝗦𝗼, 𝘄𝗵𝗼 𝗱𝗲𝗰𝗶𝗱𝗲𝘀 𝗶𝗳 𝗮 𝗖𝗔 𝗰𝗮𝗻 𝗯𝗲 𝘁𝗿𝘂𝘀𝘁𝗲𝗱?

Well, they are vetted by independent audit organizations like webtrust. 

The results of these audits are important for a CA to be trusted by web browsers and operating systems.

Now let’s look at self-managed certificates.

For internal applications, organizations often run their own private CA (PKI infrastructure).

The workflow looks like this:

- Create your own Root CA certificate and CA private key
- Generate a server private key and CSR
- Use the CA private key to sign the CSR and generate the TLS certificate
- Install the Root CA certificate in browsers or operating systems to avoid HTTPS warnings

Without installing the Root CA certificate, browsers will show security warnings because the CA is not publicly trusted.

For public endpoints, organizations always use certificates from well-known CAs (LetsEncrypt or paid ones)

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