What is TLS? A Comprehensive Guide in 4 Points


More than 4.6 billion people in the world actively use the internet, creating quintillion bytes of data on a daily basis. This data when transmitted over such a public network unprotected becomes vulnerable to modifications and attacks by malicious agents. The data, therefore, needs to be encrypted using multiple cryptographic algorithms, to protect it from tampering and keeping the source of communication secure. There are many applications that work towards securing the data and to achieve interoperability, these apps need to follow some common standard. TLS protocol i.e., Transport Layer Security protocol is one such standard that is used to communicate between the client and server. 

  1. What is TLS?
  2. Working
  3. How TLS Boosts Performance
  4. Implementation

1) What is TLS 

What is TLS? TLS stands for Transport Layer Security and in simple terms, it can be defined as a security protocol used to communicate between client and server. It is the successor of Secure Sockets Layer (SSL), first released by Netscape in 1995 and was adopted by Internet Engineering Task Force (IETF) in 1996. It thus became a globally standardized security protocol and uses an encrypted communication channel to secure data such as emails over the internet. Securing data in this manner reduces the risk of eavesdropping, interception and mail forgery.  

The TLS is an application layer protocol which helps in securely transferring data between client and server over the internet using encryption, authentication and data integrity. Most web servers use the HTTPS protocol, which is built on top of the Transport Layer Security layer. Several TLS versions are used by applications like web browsers, email, instant messaging and VoIP (Voice over Internet Protocol).  

To further elaborate on what is TLS, how TLS works needs to be understood.  

2) Working 

The TLS protocol works with the primary aim of providing privacy, security and data integrity between communicating applications. The three main components that the TLS accomplishes are:  

  • Encryption (hiding the data transferred) 
  • Authentication (authenticates the identity of the end parties and makes sure that they are what they claim to be) 
  • Integrity (verifies that the data is safe from tampering or hacking). 

The TLS consists of two sub-layers of protocols namely Handshake Protocol and Record Protocol. The handshake protocol enables the server and client to select an encryption algorithm even before sending the data and thus authenticate each other. The record protocol works on top of the TCP to ascertain that the connection is secure.  

The client (E.g., a web browser) connects to a server (E.g., a website) using the TLS and sends specifications such as a version of TLS and the cypher suites or compression methods it wants to use. The server checks the highest TLS version supported by both, selects a cypher suite and a compression method. With this setup taken care of, the server shares its certificate.

The certificate is then verified by the client or an agency trusted by it, and after ascertaining that the server is what it really claims to be a key is exchanged. This key is computed by both parties for symmetric encryption. This entire procedure of information to and from between the client and server before sending any actual data is called a handshake. Only after the handshake phase is successfully completed, the client and server can communicate securely. 

3) How TLS Boosts Performance 

The role of TLS in data communication is to ensure that the data reaches from point to point without any tampering or eavesdropping. It helps boost performance by using: 

Encryption – Data that is to be transmitted is secured using encryption techniques. 

Interoperability – The TLS protocol works on almost all operating systems and web servers as well as most web browsers. 

Deployment – It is really easy to deploy on any operating system or platform. 

Ease of use – It is easy to use and its operations are almost invisible to the client, as it’s implemented beneath the application layer. 

Flexibility – It provides operations authentication, encryption algorithms and hashing algorithms used during the secure session. 

4) Implementation 

Being so widely used, TLS also garners attention from various malicious hackers to find vulnerabilities in its algorithm or the protocol itself. It, therefore, becomes imperative that the TLS protocol is implemented in a most secure manner. The key to it lies in the foundation – its cryptographic keys. The security of the cryptographic keys that form the connection between the server and the client is essential so that no hacker gets access to these. This can be achieved by securing the key in an HSM on the server and on a secure key box (SKB) on the client side, whether they are in use or not. 


TLS is fast becoming an industry standard and many major organizations have taken the lead to implement it. It has time and again proved its worth by providing stable and reliable services and many financial institutions trust their servers with TLS encryption.  

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