SSL vs. TLS: A Beginner’s Guide to Security Protocols

Secure Socket Layer (SSL) and Transport Layer Security (TLS) are two different security protocols, but it must be noted that when it comes to SSL vs. TLS, the latter is the new and improved iteration. 

Both SSL and TLS protocols are necessary for information security, and most internet users recognize them as the famous S in HTTPS.

These two cryptographic protocols provide identity assurance and information encryption. In short, the SSL and TLS security certificates encrypt data to:

• Ensure a secure connection
• Protect sensitive data
• Prevent cybercriminals from reading or changing data

As website owners must choose one or the other, it’s important to understand the difference between TLS and SSL certificates.

In this article, we explain what each protocol is, how it works and what its benefits are for website security and your business in general. Additionally, we compare the two and discuss which protocol is superior. 

Let’s start with the predecessor – the SSL certificate.

What is SSL?

Secure Socket Layer (SSL) is a security protocol that ensures secure communication on the web. 

It encrypts data before it leaves the server and decrypts it when it reaches its destination. That way, the information is safe from prying eyes and remains available only to those on point A and point B of that information highway. 

Netscape developed the first SSL version back in 1995. However, it was riddled with problems and, consequently, was never released. SSL 2.0 quickly followed suit but wasn’t much better, so SSL 3.0 was released only a year later. 

Unfortunately, this last version still had security vulnerabilities. Things didn’t get better over time, and new security flaws, most notably POODLE and DROWN, kept popping up.

How the Secure Socket Layer protocol works

Despite the security concerns, the SSL protocol is still in use, as it offers ample protection and operates robust encryption algorithms. It works with the help of public key cryptography and follows the so-called SSL handshake process to create an encrypted link. 

Here’s how it works in practice:

1. An internet user connects to an SSL-enabled website.
2. The user’s application sends its public key and requests the server’s private key. 
3. The server decrypts the request with its own private key.
4. The message is encrypted, and only the user’s application can read it. 

If a website has the SSL protocol enabled, it has an SSL certificate granted by a trusted entity that sells and distributes SSL certificates – a Certificate Authority or CA. Certificate Authorities verify existing SSL certificates and provide new ones when necessary. 

A website with an SSL certificate always has a URL that starts with the HTTPS prefix instead of the less secure HTTP. 

Benefits of SSL

To understand the importance of using the Secure Socket Layer, take a closer look at the most important benefits of owning an SSL certificate:

• Data protection
• Identity verification
• Completion of PCI/DSS requirements
• Higher trust

SSL ensures that all data is encrypted, which protects all server-client communication. 

An SSL certificate also vouches for the identity of the website and the organization behind it. That way, when someone is communicating with an SSL-enabled website, they know who they are communicating with.

And if you want to handle online payments on your website, it must be PCI compliant. SSL certificates are one of the many prerequisites of becoming PCI compliant. 

Finally, visitors might not always know what the Secure Socket Layer protocol is, but they can recognize a secure website simply by identifying the SSL certificate.

What is TLS?

Transport Layer Security (TLS) protocol is also a security protocol that allows for data to be encrypted and protected from cybercriminals and other prying eyes. 

This cryptographic protocol also offers end-to-end security, meaning that only the sender and the receiver can view the encrypted data. Besides a web browser, it is also available for use in various other applications, including:

• Email
• Instant messaging
• Video and audio conferencing
• Voice-over-IP
• File transfers
• Internet services like NTP and DNS

The initial TLS version, TLS 1.0, was developed in 1999 using the SSL protocol and was made to fix the serious security flaws of each new SSL version. However, TLS 1.0 was flawed too. TLS 1.1 came out seven years later with some improvements (e.g., protection against cipher block chaining attacks). 

TLS 1.2 quickly followed suit, and most people chose TLS 1.2 instead of TLS 1.1. The current version, TLS 1.3., is the latest of the TLS versions, and it came out in 2018. 

The good news here is that TLS 1.3 is the best version. Unsurprisingly, many parties on the web are pushing for a wider implementation of this TLS version. 

How the Transport Layer Security protocol works

The TLS 1.3 protocol works using a combination of asymmetric and symmetric encryption cryptography. This enables a better compromise between data transmission performance and security. 

To understand this better, you need to understand the TLS handshake – the process that starts TLS-enabled communication. 

Here’s what happens in a typical TLS handshake protocol process between a client and the web server:

1. The client initiates the handshake with a message.
2. The server initiates the handshake with a message on its end.
3. The client authenticates the server’s certificate.
4. After completing the cryptographic key exchange, the client sends the premaster secret.
5. The server decrypts the premaster secret.
6. Both parties create session keys. 
7. Both now send finished, encrypted messages.

Now that you understand TLS handshakes, it’s important to mention you can also get TLS certificates as you would SSL certificates.  

CAs issue valid digital certificates that ensure clients connect to secure server systems backed by validated entities. 

Benefits of TLS

Besides the fact that the Transport Layer Security is a more modern protocol that offers better online security, there are many other benefits for businesses obtaining proper TLS protocols:

• Data integrity
• Interference and spying prevention
• Improved customer trust
• Added security in transit

With TLS, data always reaches its destination without suffering loss of information. Moreover, cybercriminals are unable to put themselves between the web server and the client. 

It’s also known that people trust sites with a proper TLS certificate. Clients are also more likely to make online transactions on sites with a TLS certificate than those without adequate security. 

It’s also important to note that this cryptographic protocol uses improved message authentication systems that better protect data while in transit. 

It’s clear that the Transport Layer Security protocol offers more than its predecessor, but what are the main differences between SSL and TLS? 

What are the differences between SSL vs. TLS?

Undeniably, the Transport Layer Security protocol is superior to SSL in many ways. Especially when it comes to actual security (thanks to the TLS Record Protocol), handshake messages and encryption strength. The other main differences are related to:

• Message authentication
• Cipher suites
• Alerts

SSL uses the message authentication code (MAC). TLS, on the other hand, uses a hash-based message authentication code (HMAC) – a combination of a hash function and a cryptographic key. Both are used after each message is encrypted. 

TLS simply uses a hash-based message authentication code for authentication, while SSL combines application data and key details ad-hoc. 

Furthermore, the SSL protocol supports the Fortezza cipher suite, while TLS doesn’t. It follows better standardization processes that more easily define cipher suites. Cipher suites are sets of algorithms that help network connection security. 

Finally, the TLS alert messages system is better than that of the Secure Sockets Layer protocol as it can send more messages. SSL effectively sends a single error message or the No Certificate alert. 

Should you use SSL or TLS?

The latest SSL version, SSL 3.0, is obsolete for many major companies, including Google. This is why Google Chrome has stopped supporting SSL 3.0. The same goes for most other notable web browsers. 

The Internet Engineering Task Force has also officially deprecated SSL protocols – SSL 2.0 in 2011 and SSL 3.0 in 2015. 

Almost all SSL certificates awarded today are effectively SSL/TLS certificates. The TLS protocol almost always replaces the Secure Socket Layer. However, the naming is only about branding, as people are more knowledgeable about SSL certificates than TLS certificates. 

Unfortunately, some sites still use SSL 2.0 or SSL 3.0. To make things worse, some of them don’t have HTTPS and are thus unsafe. 

Since TLS is officially replacing SSL all over the web, you should use the TLS protocol and strive to get a TLS certificate if you have no security protocol on your website. 

Our final tip is to avoid TLS 1.0 and TLS 1.1 as both are now obsolete due to improved newer versions. In other words, look for TLS 1.2 and, even better, TLS 1.3.

Conclusion

SSL and TLS are two crucial security protocols that ensure that the internet is safer for everyone involved. They allow companies to offer more secure services via their websites without worrying that a third party could intercept messages between them and their clients. 

TLS is newer and better as it has resolved the crucial security issues and vulnerabilities all SSL versions had. Most companies now offer TLS certificates, despite the fact that many people still refer to them as SSL certificates. If you don’t have this certificate yet, now is the time to get it. 

With the proper TLS protocol in place, your website will become more secure and you will be able to offer services that require higher security.