How Do Security Certificates Actually Work?

What is a Security Certificate?

A security certificate is a tool that websites use for validation and encryption. They are part of the HTTPS protocol which secures the flow of data between your browser and the servers of the websites you visit. Certificates are issued by a trusted certificate authority.

What is an SSL (Secure Socket Layer) Certificate?

SSL certificates are little files that bind a cryptographic key to an organization’s details. Netscape originally created this protocol to ensure transactions between web servers and browsers were secure. When an organization installs this certificate on their web server, it displays HTTPS in your browser’s address bar.

HTTPS example


If the website you’re on shows HTTPS in your address bar, this means the site is using an SSL certificate. Search Encrypt uses HTTPS to prevent your ISP or anyone monitoring your network from seeing your search terms. For website operators, it’s becoming more essential to use HTTPS because Google has started displaying warning messages on sites that use non-secure HTTP.

Read More: Let’s Encrypt is Spreading Encryption Across the Internet

Why Do You Need an SSL Certificate?

SSL Certificates are what allow websites to use HTTPS encrypted versions of their webpages. These certificates help protect the sensitive information you may enter into a given website. This includes payment information, like credit card numbers, passwords, usernames and other bits of data. If you run a website, having an SSL certificate

How Do Certificates Work?

According to, this is how SSL certificates work:

  1. A browser requests a secure page (usually https://).
  2. The web server sends its public key with its certificate.
  3. The browser checks that the certificate was issued by a trusted party (usually a trusted root CA), that the certificate is still valid and that the certificate is related to the site contacted.
  4. The browser then uses the public key, to encrypt a random symmetric encryption key and sends it to the server with the encrypted URL required as well as other encrypted http data.
  5. The web server decrypts the symmetric encryption key using its private key and uses the symmetric key to decrypt the URL and http data.
  6. The web server sends back the requested html document and http data encrypted with the symmetric key.
  7. The browser decrypts the http data and html document using the symmetric key and displays the information.

Where Can You Get a Certificate?

SSL Certificates must be issued from a trusted Certificate Authority. Most browsers, operating systems and mobile devices maintain lists of trusted CA root certificates. Most Certificate Authorities offer multiple levels of SSL. One good place to get a certificate is Let’s Encrypt. It’s a free, automated and open certificate authority. It’s sponsored by Mozilla, Cisco, EFF, Chrome, Facebook and many other reputable internet companies. There are many other authorities, like GlobalSign for example, but most of these are paid options.

How to Update Your Security Certificate

When you install an SSL certificate on your website, it will generally last for a period of one or two years. After this period is up, you will need to renew your certificate or you’ll lose out on the security you had installed. To update or renew your certificate you need to go to your certificate authority (provider) and renew through them. This should be as quick as entering your payment information and clicking OK.

Could Someone Make a Fake Certificate?

Someone could make a fake security certificate, however, the certificate has to be recognized and validated by the certificate authority. Even if a website you visit has a certificate that’s fake, the certificate authority won’t deem it to be legitimate or secure. Most browsers (besides Firefox) use the list of certificate authorities provided by your operating system. A “fake” certificate could only be validated by going through the necessary vetting that any certificate would have to go through.

The validity of a server certificate is established by: hostname, signatures of the entire certificate, additional checks to metadata, checking revocation status and checking to see if the self-signed root certificate is among the certificates that are trusted by default.

Certificates Are a Very Effective System

Certificates are used for two main functions: Encryption and Identity Verification.

  • Encryption: Information is encrypted to make sure it can only be read by approved people. Without the correct key or certificate, the information will remain in encrypted form.
  • Identity Verification: Certificates help to verify that the websites you visit and the information you view is actually coming from where it says its from.

One indication that the internet’s certificate system is effective is that you interact with these almost every time you go on the internet, but you rarely notice. The system is integrated very well with the functionality of your browser and your network connection. If a site is not secure it’s simply denoted by a lack of HTTPS. It’s not intrusive into the functionality of your browser but still lets you know if your data is at risk.

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