What is an SSL Certificate and Why is it Important?

messi62

Internet security is more important than ever, and if you have a website, protecting your users' data is critical. SSL certificates - or Secure Sockets Layer certificates - play a key role in protecting sensitive data by creating secure connections between users and websites.

This guide covers everything you need to know about SSL certificates: how they work, their types, and why every website owner needs them.

Table of contents

What is an SSL certificate?
How do SSL certificates work?
Types of SSL Certificates
Why You Need an SSL Certificate
How to get an SSL certificate?
What is an SSL certificate?
An SSL certificate is a digital document that verifies the authenticity of a website and provides an encrypted connection. This encryption is vital for protecting user data in transit, making it unreadable to any outside party. SSL, which stands for Secure Sockets Layer, has evolved into the TLS (Transport Layer Security) protocol , but the term SSL is still widely used.

When an SSL certificate is active, it enables the HTTPS (HyperText Transfer Protocol Secure) protocol, which means the site uses secure encryption. You can recognize HTTPS sites by the “HTTPS” symbol in the URL and a padlock icon in the browser address bar. These visual indicators show users that the site is secure, reinforcing confidence that any data they enter, such as passwords, credit card information, or personal data, is protected from hackers or malicious third parties.

How do SSL certificates work?
SSL certificates protect data by encrypting it during mobile app development service transmission, ensuring the privacy of sensitive information between the user and the site. The security provided by an SSL certificate is based on public key cryptography , which involves a pair of keys – a public key and a private key . Here’s how these certificates work, from start to finish, focusing on the basic steps of the SSL/TLS handshake :




Connection Request : When a user's browser attempts to connect to a site secured by an SSL certificate, the browser requests a secure connection by contacting the web server.
Server Identification : In response, the web server sends a copy of its SSL certificate to the user's browser. This certificate contains the website's public key and information about the certificate, including the issuing certificate authority (CA) and expiration date .
Certificate Verification : The user's browser verifies the SSL certificate to ensure that it is valid and issued by a trusted certificate authority. During this verification, the browser also verifies that the certificate has not expired or been revoked. If the certificate is found to be trusted, the process continues; if not, the user receives a "Not Secure" warning .
Creating a session key : Once the certificate is validated, the browser and server agree on an encryption method and create a session key – a temporary symmetric key used only for this session. The browser encrypts this session key with the site's public key and sends it back to the server.
Establishing a secure connection : The web server decrypts the session key using its private key, allowing the server and browser to use the same session key to encrypt and decrypt the data they exchange during that session. This session key allows symmetric encryption to be accelerated , providing both security and speed of data transfer.