What Is SSL and TLS? And How Does This Encryption Protocol Work?

What Are SSL and TLS? And How Do These Encryption Protocols Work?

what are ssl and tls

Online security can never be overemphasized. With all the cyber threats that exist on the internet, you are better off knowing that you have reliable protection at all times. One of the best ways to do that is with encryption. Encrypting the communications between your device and a server secures your data from third parties looking to intercept useful information.

These days, one of the most reliable and widely used encryption protocols is SSL/TLS. This powerful combination of older and more recent technology ensures that no one can snoop around data you send over the internet or a computer network. It also prevents cyber criminals and Internet Service Providers (ISPs) from tampering with your data exchange.

Although SSL/TLS is used by all secure websites and other internet services, the average user has little or no idea about what it is and how it works. That’s why this article explains what SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are, and how they operate.

What is SSL?

SSL, or Secure Sockets Layer, is an encryption protocol developed by Netspace in the mid-1990s. It was made to encrypt and secure all types of communication over the internet. When the company initially designed SSL 1.0, it was not released publicly. However, when SSL 2.0 was released, it had several flaws that could seriously compromise users. By the time Netspace released SSL 3.0 in 1996, it was built upon lessons from the preceding versions and promised to be more secure.

However, when an updated version of the protocol was released in 1999, it became standardized by the Internet Engineering Task Force (IETF) and was now known as TLS or Transport Layer Security. Despite the facelift and name change, it is still commonly referred to as SSL.

SSL/TLS are mainly used to secure communications between clients and servers, emails, VoIP, and other forms of communications that take place over unsecure internet networks. It is common to find SSL/TLS implemented on most websites because it protects important data such as passwords, payment details, and other sensitive information.

How Does SSL/TLS Encryption Work?

SSL/TLS rely on asymmetric and symmetric encryption to provide confidentiality and integrity for data transmission. Asymmetric encryption is for establishing a secure connection between the client and a server. On the other hand, symmetric encryption is for the data exchange during secure sessions.

For SSL/TLS encryption to be implemented, the website must have an SSL/TLS certificate for its web server or domain. Once the certificate is installed, it allows the client and server to negotiate the encryption through these steps:

  1. The client tries to connect to the server using a secure URL. The best way you can identify secure websites is to look out for the padlock symbol in your browser’s address bar.
  2. Next, the server sends the client its latest certificate and public key.
  3. The client then verifies the legitimacy of the certificate with a Trusted Root Certification Authority.
  4. Once the certificate is verified, both parties (client and server) negotiate the most secure type of encryption that they both can support.
  5. Next, the client encrypts a secret session key with the server’s public key and sends it back to the server.
  6. On the server end, the client communication is encrypted with its private key, and the session is established.
  7. Symmetric encryption (the session key) is used for encrypting and decrypting data transmission between the client and server.

Now, both the client and server use HTTPS (SSL/TLS + HTTP) to communicate. HTTPS function over Port 443. The moment you leave the website, the keys generated for the session are discarded. A new handshake is negotiated and new keys are generated each time you visit the website.

What is an SSL Certificate?

An SSL certificate is a file that’s installed on websites’ servers. It is basically a data file that contains the public key and identity of the website’s owners, along with other details about the website. If a website lacks an SSL certificate, its traffic won’t be encrypted with TLS.

Any website can create its own SSL certificate. These are known as self-signed certificates. The only downside is that most browsers don’t consider self-signed certificates to be as reliable as SSL certificates, which are obtained from a certificate authority.

When website owners obtain an SSL certificate from a certificate authority, the web host will have to install it on the web server. Certificate authorities are third parties that confirm that website owners are who they say they are.

Why is SSL/TLS Encryption Important for Security?

SSL/TLS encryption is excellent for securing data transmission because it boosts the privacy and integrity of data transmission. However, these days, cybercriminals are becoming more tricky and can encrypt malicious payloads that unsuspecting people fall victim to. That is why SSL/TLS decryption is important for inspection tools like IDS/IPS, next-gen-firewalls, Secure Web Gateway (SWG), and others that decrypt data as part of their inspections.

What Is The Difference Between HTTP and HTTPS?

In simple terms, the difference between HTTP and HTTPS is the S. The S stands for secure. This means that HTTPS is basically HTTP with SSL/TLS. Websites that have HTTPS addresses have an authentic SSL certificate issued by a certificate authority, and their traffic is secured and encrypted with the SSL/TLS protocol.

As we mentioned earlier, most web browsers will consider HTTP websites as “unsafe” or “not secure”. This is to ensure that all internet platforms use SSL/TLS for more security. So, SSL/TLS encryption isn’t only necessary for online security. It has also become a symbol of trust for clients and website owners.


There’s a lot that goes into protecting users’ data on the internet. It usually involves tools like encryption protocols. These protocols are like a set of instructions that clients and servers follow to provide different levels of encryption. One of these encryption protocols is SSL/TLS encryption.

Remember, your privacy is everything online. One of the best ways of protecting your privacy online is by using a top-quality VPN. You can find many online VPNs that we recommend on our review page, but one of our highest-rated VPNs is ExpressVPN.

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