What is TLS and how to ensure a secure implementation

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By Paul Butterworth


  • Secure protocol implementations define the standards for secure authentication and communication online.
  • TLS is the most common form of secure protocol used for regular internet activity.
  • TLS works by swapping keys between a certificate-verified server and client so that data shared by them can be encrypted and decrypted.
  • As it is so popular, TLS is also subject to many attacks, which means extra security measures are often needed.

What is secure protocol implementation?

A secure protocol implementation is when two entities are required to authenticate each other through a specific standardized methodology in order to securely exchange commands and data. Secure protocols are used to secure communications online with entities you don’t know, such as by web browsers when accessing different sites. A successful secure protocol implementation allows for strong verification mechanisms and safe sharing of information without creating an obstacle to communication, such as excessive delays.

What is TLS secured communication?

The most common secure protocol implementation online is Transport Layer Security (TLS). TLS is an encryption protocol that enhances the security of communication and the transfer of data over computer networks and the internet. It is widely used to encrypt all types of online communication, including across the secure internet transfer protocol “https.”

Most people come into contact with TLS secured communications when browsing online and their browser seeks to perform a “TLS handshake,” which is where the client and server initiate contact and decide the parameters of the session. This establishes a TLS secured connection with the server that’s hosting the website they want to view. It is not only web browsers that rely on TLS secured communications, however. It also provides data security across internet messaging, voice communication (VOIP) and email.

How TLS came about

The first incarnation of TLS secured communication was the Secure Sockets Layer (SSL) protocol, which was released in 1995 by browser pioneer Netscape. It was one of a variety of secure communication protocols used in the early days of the internet. SSL was found to be particularly flexible and secure, and in 1996 was adopted by the Internet Engineering Task Force (IETF) to become the globally standardized security protocol. The name was changed from SSL to TLS to differentiate it from the Netscape-only secure communication protocol.  

What does TLS do?

TLS enables network communications security by addressing three major elements that define a secure connection, namely:

  1. Privacy: Every TLS secured connection starts with a TLS handshake, where the client and server involved in the communication establish the secure keys that they’re going to use. These keys are then used to encrypt and decode the data transfers during that session. In theory, this guarantees that only the parties which have the secure keys can understand what’s being communicated, thus avoiding ‘man-in-the-middle’ attacks and message tampering.
  2. Authentication: For many TLS secured communications, such as that between a web application and server, authentication is only required on the part of the server. This means that during the TLS handshake, a secure certificate is supplied from the server-side, which authenticates its identity. Basically, it tells the client that the server is who it says it is.
  3. Integrity: A major mode of attack by cybercriminals is to tamper with communications between two parties to inject malicious data or code into devices. To prevent this, a TLS secured implementation seeks to authenticate the data that has been transferred through a Message Authentication Code (MAC). This verifies the integrity of the message and that it has not been altered during the process of communication.

The advantages of TLS secured communications

Online communications are vulnerable to a wide variety of bad actors looking to steal sensitive information, criminals looking to harness devices for use in botnets, and even state-sponsored threat groups conducting espionage and using cyberattacks to harm other countries. With trillions of interactions occurring daily, methods for securing communications and data transfers are essential to the functioning of the internet.

In this respect, TLS delivers a relatively effective and secure communication protocol for encrypting data and assuring the identities of the two communicating parties. The use of a standardized security protocol means that all web servers and clients that communicate through it are on the same page. All TLS secured communication goes through a single designated channel, port 443, while the TLS secure communication protocol also specifies the exact certificate that is required for authentication. 

For this reason, virtually all web browsers use TLS, speeding up the process of necessary TLS handshakes and the transfer of data. For example, Google, through both its Chrome browser and the algorithm it uses for search results, has pushed websites to adopt https as standard, using TLS to create a more secure environment for all online. A major question in the field has thus become how to establish the most secure TLS implementation?

How secure is TLS? Ensuring a secure TLS implementation

Because it is so widely used, TLS secured traffic gets a lot of attention from bad actors trying to find and exploit vulnerabilities in the protocol. Some common attack vectors are:

  • Through the encryption algorithm
  • Faulty implementation
  • Poorly configured servers
  • Hijacking trusted certificates
  • Weaknesses in older TLS versions which have not yet been updated

 As it is such a vital element of global infrastructure it has caused many in the cyber security community to ask just how secure is TLS.

One of the most critical issues facing a secure TLS implementation lies at the very foundation of the secure communication protocol: its cryptographic keys. If a bad actor gains access to one of the set of keys that form the connection between the two parties, it can have disastrous consequences for data integrity and the security of both client and server.

With just one set of the supposedly secure keys, hackers can pretend to be an authenticated user, using this position to gain access to TLS secured locations and sensitive data. They could also decrypt data being transferred, no matter how strong the encryption algorithm, as well as alter it by injecting malicious code. In essence, the answer to the question “how secure is TLS?” is that it’s only safe if you know that the keys of both parties are secure

Servers often use Hardware Security Modules (HSMs) which are specialized physical computing devices designed to manage cryptographic keys and perform cryptographic operations safely. They ensure that the server’s keys are kept fully protected. However, HSMs are expensive, custom pieces of equipment and it is important to remember that they only protect the server keys—they cannot authenticate the client. 

Secure Key Box for TLS

To prevent eavesdropping and message manipulation, and for the server to be assured that the client is who it claims to be, the encryption keys used by both ends of the connection in the TLS secure communication protocol need to be absolutely protected against falling into the wrong hands. This can be achieved by storing the keys in an HSM on a server, or in a secure key box, which keeps them safe on the client side, both while they’re being used and when they’re not.

whiteCryption Secure Key Box for TLS acts like a software HSM. It is the culmination of Intertrust’s efforts to deliver the most secure TLS implementation, made possible by creating a cryptographically protected library that ensures cryptographic keys never appear in the clear. It works to protect both the keys that guarantee the session’s security and integrity at the outset of each session, as well as the cryptographic keys used to encrypt and decrypt all data that’s transferred. 

To find out how our whitebox cryptographic library ensures a secure TLS implementation for end-to-end data safety and integrity, get in touch with our team today.


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About Paul Butterworth

Paul Butterworth is an experienced payment and security professional, having spent almost 30 years in the card, payments and IT security industries. Paul is responsible for global product marketing for the Intertrust Secure Systems’ market leading application shielding and device identity solutions.

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