TLS 1.2 Handshake vs TLS 1.3 Handshake

Transport Layer Security (TLS) is a security protocol used when two digital parties, often a browser and a server, engage in a handshake. During the handshake process, the browser says, in effect, “Here’s what I’m going to use to make sure the information my user sends is secure.” In reply, the server says, “Okay, based on the options you’re presenting, here’s what I think is the best way for us to interact securely.”

The tools the browser (or client) and the server can use include authentication, cryptographic protocols, and session keys. TLS determines which of these are an option for the parties during their interaction.

When two parties on the internet, such as your web browser and a website’s server, interact, they exchange TLS handshakes. This article explains:

• What the TLS 1.2 and 1.3 handshakes are
• How they’re different and similar
• The pending end of life (EOL) for TLS 1.2 and how to prepare for it

Understanding the TLS 1.2 handshake

In 1995, Netscape introduced Secure Sockets Layer (SSL) technology, a security protocol for fostering safe online transactions. Eventually, SSL was replaced by the TLS protocol, which incorporated more effective cryptographic algorithms and security features.

TLS 1.2 was first offered to the public in 2008. The goal was to improve on previous versions of TLS, developed by the Internet Engineering Task Force (IETF) to replace SSL.

TLS 1.2 grew out of a need for stronger security and offered:

• More effective cipher suites. A cipher suite is a set of algorithms used in combination with each other. TLS 1.2's algorithms were harder to crack than those in TLS 1.0 and 1.1.
• SHA-256 and SHA-384 hashing. These are secure hashing algorithms used while the server and browser verify their identities. They’re harder to break than SHA-1, which TLS 1.0 and 1.1 used.
• Better protocol version negotiation. With TLS 1.2, the client and the server could no longer use earlier, less secure protocols. By forcing them to only communicate using the most secure tools available, TLS 1.2 prevented downgrade attacks, which take advantage of earlier security protocols that are easier to break.

These features combine to provide improved security functionality when compared to TLS 1.0 and 1.1. Each handshake element results in more secure communication, authentication, and verification, such as:

• The server and the client authenticating each other’s identities
• The client and server agreeing on which cryptographic protocols to use
• Establishing a shared session key

Understanding the TLS 1.3 handshake

TLS 1.3 is is the current version of TLS. It features an even more secure handshake than TLS 1.2, making it harder to execute man-in-the-middle attacks. These types of attacks involve a hacker stealing information by positioning themselves between a browser and a web server.

Other TLS 1.3 features make it more user-friendly for both website visitors and site owners, including:

• The TLS handshake requires fewer roundtrips. These are messages sent back and forth between the client and the server. As a result, you get a secure connection faster.
• Even stronger cipher suites. Hackers used powerful computers to crack some of the algorithms that kept TLS 1.2 handshakes secure. TLS 1.3 got rid of these compromised algorithms, replacing them with more secure ones.
• Perfect Forward Secrecy (PFS). PFS makes sure that each session key is completely independent of long-term private keys, which are keys a user or system uses for an extended period to decrypt encrypted data. This means that even if someone cracks a long-term private key, they can’t use it to figure out what the session key is.
• Zero round trip time resumption (0-RTT). This enables clients to send data in the very first round trip, reducing the amount of time it takes to form a secure connection.
• Superior privacy. TLS 1.2 vulnerabilities allowed hackers to steal user information. TLS 1.3 addressed and eliminated these vulnerabilities.

Key differences between TLS 1.2 and TLS 1.3

When juxtaposed, the differences between TLS 1.2 and 1.3 are clear, and this is good news for business and individual internet users:

• 0-RTT. With TLS 1.3, zero round trip time resumption results in a faster, more secure handshake between clients and servers. This means whether you’re making a purchase, placing a stock order, or sending rapid-fire WhatsApp messages, you have less latency to deal with.
• Handshake speed. With TLS 1.3, the handshake speed is faster, which means real-time applications and Internet of Things (IoT) devices can interact with servers with less latency. The result is a smoother user experience without compromising security.
• Secure cipher suites. Insecure, compromised ciphers were an issue with TLS 1.2. By eliminating these, 1.3 makes the internet safer.
• Performance efficiency improvements. TLS 1.3 improves efficiency in the handshake process by requiring fewer roundtrips than 1.2. It also uses cryptographic algorithms that are faster. As a result, the handshake takes less time and computational power.
• Security enhancements. TLS 1.3 has better security than TLS 1.2. It addresses known vulnerabilities in the handshake process, such as algorithms that hackers have found a way to crack. For example, TLS 1.2 was vulnerable to padding oracle attacks that take advantage of SSL 3.0 encryption to expose sensitive data.
• Other differences. TLS 1.3 got rid of data compression, which some hackers exploited to steal information. Also, once a client and a server have established a secure connection, with TLS 1.3, they can connect again without any roundtrips. This also makes the handshake faster.

Similarities between TLS 1.2 and TLS 1.3

Even though the two protocols are different, they have the same objective at heart: to enable secure connections online. They’re also both used to secure online transactions, making it safer to submit payment information through the internet, for instance.

One of the biggest similarities between TLS 1.2 and 1.3 is that they both use a handshake system to establish a secure connection. Key-based encryption algorithms are essential elements of each protocol's handshake.

You can think of TLS 1.2 as an old Windows Vista operating system and TLS 1.3 as Windows 11. Even though they have the same basic purpose, the newer version is faster and more secure.

TLS 1.2 end of life

The timeline for TLS 1.2's EOL is hard to set in stone. Over time, as hackers crack systems, they become less and less secure, forcing their EOL. TLS 1.0 and 1.1 reached their EOL in January 2020. Having been released in April 2006, TLS 1.1 had a lifespan of a little under 14 years. So it's reasonable to expect TLS 1.2's deprecation or EOL very soon because it’s already been around for 15 years.

Legacy systems that still depend on TLS 1.2 may soon not be able to interface with internet-based assets as they’d like. This could introduce significant challenges, such as the need to upgrade servers and transition data and configurations over to your new system.

Here are some best practices for making the transition from TLS 1.2 to TLS 1.3:

• Check your servers' and clients' compatibility with TLS 1.3.
• Update your systems' firmware. Many of them may support TLS 1.3, which increases the number of compatible devices you have.
• Always test in a safe staging environment before going live.
• Refresh your security policies to reflect your upgrade to TLS 1.3. This lets system users know you’ve made the switch and to make any configuration adjustments that may be needed on their end.
• Don’t forget to monitor and document any performance improvements. By making these known to customers and other stakeholders, you build confidence in your upgrade—as well as your organization.

Why this matters for your network's security

TLS 1.2 and TLS 1.3 are different in that TLS 1.3 is faster, more efficient, and more secure. The latest version of TLS, 1.3, lets you create a more secure experience for users and reduce the vulnerabilities that could create extra work for your IT team.

Sectigo’s TLS certificates come with the latest security features, which foster safer, faster connections to your digital assets. With the Sectigo Certificate Manager, you can discover, issue, and renew all your digital certificates using one platform. Learn more about how Sectigo supports a more robust security posture by setting up a demo today.

Want to learn more? Get in touch to book a demo of Sectigo Certificate Manager!