Difference Between SSL and TLS: Key Security Insights

Cybersecurity, as a technology, has evolved with the rise of cyber threats. Cyber threats over time have become more and more lethal. To keep those threats away there has been a lot of research and development done. As a result, SSL (Secure Sockets Layer), TLS (Transport Layer Security) have emerged as new protocols to ensure web security.  There are certain differences between the SSL and TLS protocols with one being the successor of the other.

In terms of similarities, SSL and TLS both provide encryption of online communications and take things further from the days of the Hypertext Transfer Protocol (HTTP). HTTP was an initial breakthrough in making websites secure. However, evolving threats demanded something more secure. That is where SSL and TLS came into the picture. Now, to understand the difference between SSL and TLS, we have to understand their basics.

What is SSL

SSL (Secure Sockets Layer) was developed back in the days of the World Wide Web (www) led by Taher Elgamal at Netscape. The release of SSL 2.0 provided for secure communication over the Internet. It utilized cryptographic techniques to provide encryption for sensitive details.  The SSL 3.0 came in as the most advanced version of the protocol in the 90s. It kept the internet safe for over a decade and then made way for the TLS protocol. SSL is now deprecated as a cybersecurity protocol

The TLS Protocol

TLS (Transport Layer Security) first came out in 1999, thanks to the efforts of Christopher Allen and Tim Dierks. TLS is the successor of the SSL protocol, and like SSL, it uses a handshake process.  It utilizes digital certificates to create an encrypted connection between a web browser and the server. The similarities between SSL and TLS often led to the use of the two terms interchangeably. However, currently, SSL/TLS is commonly used for the TLS protocol. As per statistics, over 70% of total websites on the internet were using the latest TLS protocol. So, if we closely look at the difference between SSL and TLS, it comes down to the fact that one is an old protocol while the other is a successor protocol.

Difference between SSL and TLS

The basic difference between SSL and TLS is that SSL, being older, is more vulnerable to cyber threats. TLS, being a successor, works on those loopholes and provides more secure communication between the server and the browser. The first version of TLS, which is TLS 1.1, came about two decades ago. This was 6 years later than the launch of SSL 3.0 at a time when the use of the internet was expanding.

The latest version of TLS is TLS 1.3, which was finalized back in 2018. Adoption of TLS by technology majors like Google, Apple, Mozilla, and Microsoft brought an end to SSL. At present, apart from TLS 1.2 and TLS 1.3, there is no advanced security protocol. 

A handful of websites still operate on the SSL and HTTP protocols, which means they are an easy prey for cyber threats. Being outdated, SSL and HTTP cannot achieve the level of protection that can stand as a wall to modern-day cyber threats. While SSL had encryption to secure communication, HTTP didn’t even have secure or encrypted communication. 

At the time of HTTP, back in the 90s, the internet was yet to become widespread. Given the limited load and security threats, it served the needs of the time pretty well. Towards the latter half of the 90s, with the IT boom and expansion of the internet, the need for an upgraded protocol was felt. That is when SSL was developed, and in the late 90s till 2010-15, it was serving the cyber world. However, the loopholes in SSL made it vulnerable to modern security threats. That is where the TLS started to gain traction and become the sole and most advanced protocol. 

If you see it as an evolution of cybersecurity, HTTP made way for SSL, which was then replaced by TLS. With the emerging trends and threats in cyber world, the security parameters keep on evolving. In the future, we will see a more advanced version of TLS. Eventually, it would also make way for a new set of protocols. For now, TLS still has got a lot to offer in terms of ensuring secure online communications.

Mechanism: SSL and TLS 

The mechanism and operation of SSL and TLS are the same, and they are based on cryptographic encryption of data. Each version tries to fix the shortcomings of the other, while the overall fundamentals of operation remain the same.

In the handshake process, the browser authenticates the server’s SSL or TLS certificate. In the case of SSL, the handshake process utilizes a larger number of steps. In a sense, the handshake process in SSL is an explicit operation. 

However, in the TLS protocol, the handshake process is an implicit function. Which means the TLS protocol removes additional steps and makes the process quicker. In SSL, the alert messages that come in the handshake process are warning and fatal. These alert messages are not encrypted. The warning message raises a concern flag, but allows the connection to proceed. Fatal message, however, calls for an immediate termination of the connection.

In TLS, apart from the warning and alert messages, there is an additional close notify message. This marks the end of the session. Further, the alert messages that are generated in the TLS are encrypted, unlike the SSL ones, which are not encrypted. 

Conclusion

The difference between SSL and TLS, as we discussed in detail, is not more than that of a predecessor and a successor. In layman’s terms, both SSL and TLS are used interchangeably. However, in reality, each version and protocol is an upgrade, making the connection more secure. As a website owner, it is important to use the latest version of the protocol to avoid cyber threats. Given the fact that tech majors are opting for and recommending TLS, it’s a wise decision to get your website in sync with the protocol. At Provis Technologies, we always recommend staying updated with the latest security standards to ensure your website remains protected.