TLS 1.2 vs TLS 1.1

Updated on February 22, 2023

In today's world, security is a crucial aspect of every aspect of our lives. With the internet being an integral part of our daily routine, it is important to ensure that our online transactions are secure and protected from malicious attacks. One of the ways to ensure this is by using secure communication protocols such as Transport Layer Security (TLS). In this article, we will be discussing the differences between TLS 1.2 and TLS 1.1, two widely used versions of TLS.

What is TLS?

TLS stands for Transport Layer Security, which is a cryptographic protocol used to increase security over computer networks. TLS is the successor of SSL although is sometimes still referred to as SSL. TLS has been evolving as time passes to keep up with more complex security requirements, to fix cryptographic flaws, etc. The section below shows a quick timeline of the variations of TLS versions.

TLS 1.0 - Released in 1999 and published as RFC 2246. This version of TLS was very similar to SSL 3.0
TLS 1.1 - Released in 2006 and published as RFC 4346.
TLS 1.2 - Released in 2008 and published as RFC 5246.
TLS 1.3 - Released in August 2018 and published as RFC 8446.

To explain the differences between TLS 1.2 and TLS 1.1, we'll outline what changes took place in relation to the previous version of TLS.

TLS 1.1

As previously mentioned, TLS 1.1 was released in 2006 and is the second version of TLS. According to RFC 4346, the major differences that exist in TLS 1.1 compared to TLS 1.0 include the following:

The implicit Initialization Vector (IV) is replaced with an explicit Initialization Vector for protection against Cipher Block Chaining (CBC) attacks.
Padding error handling is modified to use bad_record_mac alert rather than decryption_failed alert. Again, to protect against CBC attacks.
IANA registries are defined for protocol parameters.
A premature close no longer causes a session to be non-resumable.
Additional notes were added regarding new attacks and a number of clarifications and editorial improvements were made.

TLS 1.2

TLS 1.2 is currently the most used version of TLS and has made several improvements in security compared to TLS 1.1. According to RFC 4346, the major differences that exist in TLS 1.2 when compared to TLS 1.1 include the following:

The MD5/SHA-1 combination in the pseudorandom function (PRF) is replaced with SHA-256 with the option to use the cipher-suite-specified PRFs.
The MD5/SHA-1 combination in the digitally-signed element is replaced with a single hash which is negotiated during the handshake.
Improvements to the client's and server's ability to specify the accepted hash and signature algorithms.
Support for authenticated encryption for other data modes
TLS extensions and AES cipher suites were added
Tightened up various requirements

The greater enhancement in encryption of TLS 1.2 allows it to use more secure hash algorithms such as SHA-256 as well as advanced cipher suites that support elliptical curve cryptography. To check if a particular https:// web page is using TLS 1.2 encryption, you can run it through an ssllabs test. The results will provide you with information regarding what the site is using for security protocols, the cipher suites, etc.

What improvements does the TLS 1.2 version bring?

Cipher suites

Cipher suites are a set of cryptographic algorithms that are used to encrypt and decrypt data. TLS 1.2 introduces new cipher suites that are more secure than the ones used in TLS 1.1. TLS 1.2 supports Advanced Encryption Standard (AES) cipher suites, which are more secure than the Triple Data Encryption Standard (3DES) cipher suites used in TLS 1.1. AES is a block cipher that uses a 128-bit key, which makes it more secure than 3DES, which uses a 168-bit key. In addition, TLS 1.2 introduces new hash algorithms, such as SHA-256 and SHA-384, which are more secure than the SHA-1 algorithm used in TLS 1.1.

Handshake protocol

The handshake protocol is used to establish a secure connection between a client and a server. TLS 1.2 introduces some changes to the handshake protocol that make it more secure than the one used in TLS 1.1. TLS 1.2 uses a more secure method of generating random numbers during the handshake process, which makes it more difficult for an attacker to guess the random numbers and launch a man-in-the-middle attack. In addition, TLS 1.2 introduces support for Elliptic Curve Cryptography (ECC), which is more secure than the RSA algorithm used in TLS 1.1.

Renegotiation attack

TLS renegotiation is a feature that allows a client and a server to renegotiate the cryptographic parameters of an existing connection. This feature was found to be vulnerable to a type of attack called the renegotiation attack. TLS 1.2 addresses this vulnerability by introducing a new renegotiation extension that prevents this type of attack.

Padding

Padding is used to fill out the plaintext of a message so that it is the same size as the block size of the cipher used to encrypt the message. TLS 1.1 allows for the use of insecure padding schemes such as the SSL 3.0/TLS 1.0 padding scheme, which is vulnerable to attacks such as the BEAST attack. TLS 1.2 introduces new padding schemes that are more secure and resistant to attacks.

Backward compatibility

TLS 1.2 is not backward compatible with TLS 1.1 or SSL 3.0. This means that servers and clients that support only TLS 1.1 or SSL 3.0 will not be able to communicate with servers and clients that support only TLS 1.2. However, most modern web browsers and servers support TLS 1.2, so backward compatibility is not an issue in most cases. In addition, most servers and clients that support TLS 1.1 also support TLS 1.2, so upgrading to TLS 1.2 should not be a problem.

Performance

TLS 1.2 is faster than TLS 1.1 due to several improvements in the protocol. TLS 1.2 reduces the number of round trips required during the handshake process, which reduces latency and improves performance. In addition, TLS 1.2 uses more efficient cipher suites, which also contribute to better performance.

Security vulnerabilities

TLS 1.1 has several security vulnerabilities that have been discovered over the years. For example, the BEAST attack, which exploits the SSL 3.0/TLS 1.0 padding scheme, affects TLS 1.1. In addition, TLS 1.1 is vulnerable to the Lucky Thirteen attack, which exploits the way that the cipher block chaining (CBC) mode of operation is used in TLS. These vulnerabilities are not present in TLS 1.2, which is more secure and resistant to attacks.

Industry support

TLS 1.2 is supported by most modern web browsers and servers and is widely used to secure online transactions. In contrast, TLS 1.1 is becoming less common and is being phased out by many organizations. This is because TLS 1.1 has several security vulnerabilities and is not as secure as TLS 1.2. In addition, TLS 1.2 is required for compliance with many security standards and regulations, such as the Payment Card Industry Data Security Standard (PCI DSS).

What's next - TLS 1.3

TLS 1.3 was officially released in August 2018 and has been gaining popularity in the years since then. It is the latest version of the Transport Layer Security protocol and offers several improvements over its predecessor, TLS 1.2.

TLS 1.3 is designed to be faster, more secure, and more resistant to attacks than TLS 1.2. It reduces the number of round trips required during the handshake process, which reduces latency and improves performance. It also includes several security improvements, such as support for stronger cipher suites and more secure algorithms for key exchange and digital signatures.

TLS 1.3 has been adopted by major web browsers such as Google Chrome, Mozilla Firefox, and Microsoft Edge, as well as by popular web servers such as Apache and Nginx. However, some older devices and servers may not support TLS 1.3, so it may not be possible to use it in all situations.

As of February 2023, TLS 1.3 is the recommended version of the TLS protocol for securing online transactions. It is supported by most modern web browsers and servers and is widely considered to be the most secure version of the protocol to date.

Overall, TLS 1.3 represents a significant improvement over TLS 1.2 and offers the highest level of security and performance for online transactions. As the internet continues to evolve and security threats become more sophisticated, it is likely that TLS 1.3 will become even more important in securing online communication.