TLS stands for “Transport Layer Security.” It’s an encryption protocol that keeps your data safe while using HTTPS websites. It encrypts your information, making sure that it stays private as it travels between your browser and the website. While this type of encryption is also used for email and messaging, it’s primarily used to secure regular web traffic.
Unlike HTTP — which sends data over the internet as plain text — HTTPS (powered by TLS) encrypts everything. This means that even if someone intercepts your data, they can’t read or use it. For instance, when you enter sensitive information such as your credit card details on a secure website, TLS encrypts that information, thereby protecting it from hackers.
Though SSL (Secure Sockets Layer) was the original encryption standard, TLS has taken over because it offers stronger security and better performance. But there’s more to the story than that — there are additional steps you should take to protect yourself online, like using a good VPN (such as ExpressVPN). Learn more about TLS, HTTPS, and online safety now. Editors' Note: ExpressVPN and this site are in the same ownership group.
How Does TLS Encryption Work?
TLS establishes a secure connection between your browser and a website. This process involves several key steps that ensure both data privacy and integrity, making sure your information remains protected throughout the communication cycle.
The TLS Handshake
The TLS handshake is the crucial first step in establishing a secure connection between your browser and a website. During this process, the client (your browser) and the server exchange cryptographic keys and agree on the encryption methods that will be used throughout the session.
Essentially, the handshake involves asymmetric encryption, where the server provides a public key that the client uses to encrypt information. Only the server, with its private key, can decrypt this information. This ensures that the communication channel is secure and that both parties are legitimate.
The handshake also involves selecting a cipher suite, which is a set of algorithms that will handle encryption, decryption, and the authentication process. Once the handshake is complete, a session key is generated. This key is then used to encrypt the data exchanged during the session, ensuring that any sensitive information remains protected.
Session Keys and Symmetric Encryption
Once the TLS handshake is complete, the connection switches to symmetric encryption, which uses session keys. Unlike asymmetric encryption, where different keys are used for encryption and decryption, symmetric encryption relies on a single, shared session key. This method is much faster and more efficient, making it ideal for securing large amounts of data during an active session.
The session key is temporary and unique to each session, meaning that even if it were somehow compromised it would not affect other sessions. This temporary nature of session keys adds an extra layer of security, as a new key is generated each time you connect to a website using TLS. This combination of speed and security makes symmetric encryption a cornerstone of TLS, ensuring that your data is both protected and transmitted efficiently.
Data Integrity
TLS does more than just encrypt your data — it also ensures that the data hasn’t been altered during transmission. This is achieved through a mechanism known as a Message Authentication Code (MAC). After data is encrypted using the session key, it is also signed with a MAC. When the data reaches its destination, the MAC is checked to verify that the data has not been tampered with.
This process guarantees data integrity, which is critical for maintaining trust in online communications. For instance, if you’re sending payment details or personal information, TLS ensures that the data arrives exactly as it was sent, without any alterations. This is why TLS is considered essential for secure online transactions.
TLS Versions and Their Evolution
TLS has evolved significantly since its inception, with each version offering enhanced security and improved performance. The original SSL (Secure Sockets Layer) protocol, which TLS replaced, was vulnerable to several security flaws. TLS 1.0, introduced in 1999, addressed many of these issues, but further improvements were needed. TLS 1.1 and TLS 1.2 introduced stronger encryption methods and improved security protocols, making them more resistant to attacks.
The most recent version, TLS 1.3, represents a significant leap forward in security. It eliminates outdated cryptographic algorithms and reduces the time required to establish a secure connection, making it both faster and more secure. The adoption of TLS 1.3 has been crucial in countering modern cyber threats, ensuring that data protection keeps pace with the increasing sophistication of online attacks.
Real-World Applications of TLS
TLS is most commonly associated with securing websites via HTTPS, but its use extends beyond that:
- Email Communications: TLS is used to encrypt emails during transmission, protecting sensitive information from interception and ensuring secure communication between email servers.
- Instant Messaging and VoIP: TLS encrypts communications in instant messaging and Voice over IP (VoIP) services, preventing eavesdropping and unauthorized access to conversations.
- Virtual Private Networks (VPNs): TLS is employed in VPNs to create secure tunnels for data transmission. (Learn more about how VPNs work here.)
The Downfall of SSL
SSL was once the standard for securing online communications, but over time, it became clear that it had significant vulnerabilities. These weaknesses allowed attackers to exploit flaws in the protocol, potentially intercepting or tampering with the data being transmitted.
Noteworthy attacks like POODLE (Padding Oracle On Downgraded Legacy Encryption), which allowed bad actors to decrypt SSL traffic, highlighted SSL’s inability to protect against certain types of attacks, leading to widespread concerns about its reliability.
As a result, the industry moved away from SSL in favor of TLS, which addressed many of SSL’s shortcomings. TLS introduced stronger encryption algorithms and more powerful security features, making it much harder for attackers to compromise secure connections.
Today, SSL is considered obsolete and is no longer recommended for securing data. Most modern websites and online services have transitioned to TLS, with the newest iteration being TLS 1.3. Today, whenever you see “https”, the website is more than likely using TLS encryption.
Why TLS Is Important for Online Security
TLS is essential for protecting your online activities. Here’s what it does:
- Protects data in transit: TLS encrypts data as it moves between your browser and the server, making it inaccessible to hackers and eavesdroppers. This encryption is vital for preventing sensitive information, such as passwords and credit card details, from being stolen during transmission. Without TLS, any data sent over the internet could be easily intercepted and read by malicious actors.
- Ensures data integrity: By using cryptographic methods, TLS ensures that the data you send and receive has not been altered or tampered with during transmission. This protection is crucial for maintaining the trustworthiness of online communications, as even a slight alteration of data could have serious consequences, such as financial fraud or identity theft. With TLS, you can be confident that the information you receive is exactly what was sent.
- Verifies website authenticity: TLS helps confirm that the website you’re connecting to is legitimate, preventing man-in-the-middle attacks where an attacker could impersonate a trusted site. This protection is especially important for online banking and shopping.
- Establishes trust in online interactions: Websites using TLS display the padlock icon in the browser, signaling to users that their connection is secure. This visual cue helps build trust between users and websites, encouraging more secure online transactions and interactions. When users see the padlock and HTTPS, they are more likely to feel confident in sharing sensitive information and conducting business online.
The Role of a Certificate Authority (CA) in TLS Security
Certificate Authorities (CAs) are essential in making sure you can trust the websites you visit. They issue digital certificates that verify a site’s identity, ensuring that when you see HTTPS in your browser you’re connected to a legitimate website, not an impostor. Your browser relies on these certificates to confirm that the site is secure.
There are different levels of certificates issued by CAs, each with varying degrees of validation. For example, Domain Validated (DV) certificates only verify that the domain is owned, while Organization Validated (OV) and Extended Validation (EV) certificates require more thorough checks, especially for businesses. EV certificates are the most difficult to obtain and often display special indicators in your browser.
For instance, major companies like Amazon or your bank would likely use an EV certificate to show that they’ve gone through rigorous validation and to provide maximum trust to their users. On the other hand, a personal blog might use a DV certificate, which is easier and quicker to obtain but still provides essential encryption.
Why TLS Encryption Alone Isn’t Enough to Protect You
While TLS encryption is highly effective at securing individual connections, it has its limitations. TLS only protects the data sent between your browser and the website you’re visiting. This means that other online activities, like using apps, streaming, or connecting to non-secure websites, might still leave your data vulnerable.
Additionally, TLS doesn’t hide your IP address, which can still be tracked by your Internet Service Provider (ISP) or other third parties. This is where a VPN comes in.
A good VPN provides more comprehensive protection by encrypting all of your internet traffic, not just your web browsing. With a VPN, every piece of data you send or receive — whether through an app, a non-secure site (HTTP), or any other online service — is encrypted and hidden from prying eyes. A VPN also masks your IP address, making it much harder for anyone to track your online activities or determine your physical location.
Using a VPN (like ExpressVPN) and only visiting HTTPS websites is the best way to stay safe online. This combination is particularly useful for maintaining privacy and security in situations where your data might be at risk, like when using public Wi-Fi or submitting sensitive information online.
Editors' Note: ExpressVPN and this site are in the same ownership group.
Frequently Asked Questions
What is TLS encryption used for?
TLS encryption is used to secure data transmission over the internet, particularly for web browsing, email, messaging, and online transactions. It ensures that the data sent between your device and a server is encrypted, protecting it from unauthorized access.
TLS is most commonly seen in HTTPS, where it safeguards sensitive information like passwords, credit card numbers, and personal data from being intercepted by malicious actors. It’s also used in securing email communications, instant messaging, and other applications where privacy and data integrity are critical.
What’s the difference between SSL and TLS?
SSL and TLS are both protocols used to secure data transmission, but TLS is the more modern and secure version. SSL (Secure Sockets Layer) was the original protocol, but due to various vulnerabilities, it was replaced by TLS (Transport Layer Security).
TLS improves upon SSL by offering stronger encryption algorithms and enhanced security features, making it more resistant to attacks. Over time, TLS has become the standard for securing online communications, and SSL is no longer considered safe to use. Most websites and services today have transitioned to TLS, with SSL now largely obsolete.
Is TLS encryption good?
Yes, TLS encryption is highly effective at protecting data transmitted over the internet. It ensures that the information exchanged between your device and a server remains private and secure, preventing unauthorized access or tampering.
However, TLS by itself isn’t enough to fully protect your online privacy. While TLS secures specific connections, it doesn’t cover all your online activities or hide your IP address. To enhance your overall security, using a VPN in conjunction with TLS is recommended. A VPN encrypts all your internet traffic and masks your IP address, providing an additional layer of privacy and security across all your online activities.
What is the difference between TLS and encryption?
TLS is a specific protocol that uses encryption to secure data, while encryption itself is a broader concept that refers to the process of converting data into code to prevent unauthorized access. In essence, TLS relies on encryption to protect information during transmission.
Encryption is the core technology used within TLS to secure data as it travels between a client and a server. While encryption can be used in various contexts outside of TLS, such as file encryption or disk encryption, TLS specifically applies encryption to secure online communications, making it a specialized application of the broader encryption concept.