What Is VPN Encryption? Everything You Need to Know

You’ve probably seen VPNs claiming to use advanced encryption to keep your data secure. VPN encryption can get pretty complicated, but essentially, it’s a set of complex algorithms that change your data so unauthorized people can’t make sense of it even if they manage to access it. Of course, there’s a lot more to it than that. 

As Ghosties, we like to keep things simple – so we’re going to explain everything you need to know about encryption in the least complicated way possible. Let’s dive into exactly what encryption is, how it works, and what it means for your online security.

Glossary

Let’s start by defining some of the terms you’re going to see here: 

Algorithm	A sequence of rules or instructions that determine how a device will perform a task.
Asymmetric encryption	Encryption that uses a public and private key to secure your data. The public key is used to encrypt your data and the private key is used to unlock or decode it at the other end.
Cipher	A type of algorithm used for encrypting and decrypting data, switching it from plaintext to ciphertext. It determines how your data will be transformed before being transferred across the web.
Ciphertext	Plaintext (unchanged data) that is changed using an encryption cipher to make it unreadable without the right key.
Cryptography	The practice of securing your traffic using cipher algorithms.
Data packet	Small units of data that are transferred over a network. Traffic is broken up into several data packets for transfer.
Data block	Individual data packets are grouped together to form a data block.
Decrypt	The process of turning ciphertext back into plaintext so it can be understood.
Encapsulation	The process of protecting data packets by wrapping them in other layers of information before transmission. These layers of information function as a protective cover, making it harder to find the real data underneath.
Plaintext	Normal, readable web traffic that can be understood by anyone.
Public key	The key used to encrypt and decrypt your data. Both the sender and receiver of data have the shared public key.
Private key	Another key used to decrypt your data via asymmetric encryption. Only the receiver has the private key needed to decrypt data.
Request	When your device communicates with a web server seeking access to a resource.  This happens when you interact with websites and apps, such as when you open a URL, click a button or link, or enter information into a search bar.
Symmetric encryption	Encryption that uses the same public key to encrypt and decrypt your data.
Tunneling	The process of establishing a secure connection between your device and the VPN server so data can be sent using encryption.
VPN tunnel	The private pathway established between your device and the VPN server is called a tunnel. All data travels through this tunnel.
VPN (tunneling) protocol	A set of rules determining how a VPN establishes a secure tunnel and then transfers data through it.

What Is VPN Encryption?

VPN encryption is a process that uses a cipher algorithm to convert your normally readable internet data into a secret code before it leaves your device. To fully understand what this means, let’s break it down.

When you browse the web, stream videos, or send messages, your data doesn’t travel as one big chunk. Instead, your device breaks it down into small units called data packets. These packets contain pieces of your information, along with metadata that helps routers and servers understand where the data is going and how to reassemble it at the other end.

Without encryption, these packets travel across the internet in plaintext. That means hackers, your ISP, and even surveillance agencies can intercept them and see exactly what you’re doing online. VPN encryption prevents this by applying a cipher to transform your data packets. The cipher is a complex mathematical function that systematically replaces your readable data in each packet with random-looking characters, turning it into ciphertext.

You need a unique key to “undo” the encryption and turn your traffic back into plaintext. Your VPN software generates this unique key for your session and shares it over a secure connection with the VPN server. This means no one else has access to the key to decrypt your information, which is part of why encryption is almost impossible to break through. Without this key, your data will remain encrypted, essentially ensuring that outsiders can’t see what you’re doing online. 

Why Should You Encrypt Your Data?

Encryption is one of the best ways to protect your data (both online and offline) against falling into the wrong hands. Whenever you go online, your requests are sent through your ISP’s network. It connects your local network to the world wide web, and redirects each request to the specific site or service you’re trying to reach. In other words, your ISP sees everything you do online.

Others could be watching, too. Government officials, cybercriminals, and Wi-Fi owners could be following you around the web collecting information about you. They have different goals: cybercriminals might steal your private information to commit crimes like identity theft and fraud, officials could be enforcing censorship, and Wi-Fi owners may want to spy on you or sell your data. 

Encryption helps you avoid this unwanted surveillance. Changing your plaintext data to ciphertext means that outsiders can’t see what you’re doing online, preventing data theft and spying. 

Encryption offers other benefits beyond security. It also lets you dodge firewall limits and unblock websites on restricted networks by masking your traffic before it leaves your device. This means your website requests are hidden from network admins and firewalls, so you can access sites an admin might have blocked. For example, VPN encryption will let you access social media and streaming platforms such as Netflix and Disney+, YouTube, and ChatGPT even if they’re blocked on your work or school’s Wi-Fi. 

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Types of VPN Encryption

Now that we know what VPN encryption is and why it’s useful, let’s move on to the two main types of VPN encryption – as this will help you understand the encryption process. CyberGhost VPN applies a combination of both encryption methods to safeguard your data.

Symmetric Encryption

Symmetric encryption uses the same key to secure data traveling between two devices or applications. The participants (in this case your device and the VPN server) use a mathematical equation to generate a shared key which they both use to encrypt and decrypt data. 

You could think of it in terms of sending a password-locked email to a friend. You both first agree upon a secret shared password, then you use that password to lock the email. When your friend receives the email, they use the same password to open it. 

Asymmetric Encryption

Asymmetric encryption uses a public and private key combination to secure data, and both devices use a unique pair of keys to encrypt and decrypt any data they send to each other. 

Say you want to send another private email to your friend. First, you would both use a mathematical equation to create a public and private password pair for each of you. Then you’d exchange your public passwords. After that, you’d use your friend’s public password to encrypt the email before sending it. Your friend can only decrypt the email with their private password. If they reply, your friend would use your public password to encrypt their response and only you can use your private password to decrypt it.

This means that even if someone has your public keys (passwords), they wouldn’t be able to read your emails without the private keys. It’s like an extra password you need to decode the message.

How Does VPN Encryption Work?

VPN services use different encryption techniques depending on how they’ve engineered their systems. CyberGhost VPN uses hybrid encryption – in other words, we rely on a combination of symmetric and asymmetric keys to establish a secure connection and transfer your data. Premium VPNs typically employ a similar encryption method as it’s considered the most secure setup available. 

When you connect to a VPN, it establishes a secure tunnel between your device and its server using a method called tunneling. Your VPN app will likely share a symmetric key with the VPN server at this time, so the server can decrypt the data it receives from your device and vice versa. A VPN protocol determines how this tunneling process works.

Before the VPN sends your encrypted data packets to the VPN server, it may also encapsulate each packet with unimportant information to add another layer of protection. The encapsulation process works similarly to wrapping paper, preventing outsiders from easily viewing your data unless they go through the trouble of unwrapping each layer. 

Let’s walk through an example of how this works when you establish a CyberGhost VPN connection:

1. Your VPN app creates a secure connection to a VPN server using instructions from the VPN protocol.
2. During this process, the VPN app and server generate an asymmetric public-private key pair and exchange their public keys.
3. The VPN app and server then generate a secret symmetric key. Since this exchange is secured using asymmetric encryption, no one can see the shared symmetric key without having one of the private asymmetric keys.
4. When you send a connection request to a web server (such as Google), the VPN app breaks your data into smaller packets and encrypts each packet using 256-bit AES symmetric encryption with the shared key. This turns your plaintext data into ciphertext.
5. The VPN changes the routing information in the IP header of this request to its server’s IP address and encapsulates your data packets.
6. The VPN then sends the request through your ISP’s network to the VPN server, which removes the encapsulation from each data packet and uses the shared encryption key to decrypt your data.
7. CyberGhost VPN also uses its servers to handle your DNS request so your ISP (or a third-party DNS service) can’t track your activity through your DNS requests instead of your IP requests.
8. The VPN server replaces your IP address with its own and forwards your decrypted data to the destination web server (in this case Google) as if the connection request comes from the server instead of your device.
9. Google sends data back to the server, which encrypts and encapsulates this data using the shared key again before sending it back to your device.
10. Your VPN app removes the encapsulation and then decrypts your data packets using the same symmetric encryption key.

It sounds long and complex, and it is, but you won’t notice this process happening. VPN encryption ciphers and deciphers your information in seconds. You don’t need to do anything yourself other than choose which server location you want to connect to. The result is that no one can see what you’re doing online while your data is transmitted through the VPN tunnel.

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What Is AES Encryption?

AES encryption is a type of encryption algorithm that uses symmetric keys to secure your data. It’s called the Advanced Encryption Standard (AES) because it’s one of the most effective encryption algorithms publicly available. 

Rather than sending all your data at once, AES encryption splits your information into small blocks. This is why it’s also known as a block cipher. Every block or data packet has a unique cryptographic key, which relies on data from the previous block to unlock it. Once the recipient device has determined a block has arrived safely, it can then unlock the next block. This way, if anyone happens to get access to a block and somehow manages to decipher its contents, only a small amount of data is affected, not the whole piece of information. 

How AES Encryption Works

As mentioned earlier, keys come in different sizes, which is why you might have seen VPNs offering 128-, 192-, and 256-bit AES encryption. As you’d expect, it takes much longer to decrypt blocks of text that went through 2^256 possible combinations of changes than it would to decode blocks of text that went through 2^128 possible combinations. Much like it would take more time to guess a long password versus a short one. Thus, the longer the key, the more secure it is.

To put this into context, imagine your data packets each form a completed jigsaw puzzle. This is what AES-256-bit does to your data:

1. The algorithm generates a 256-bit key, and both participants share this secret (symmetric) key.
2. It takes each data packet from the sender (in sequence) and deconstructs it into groups of 16 “puzzle pieces” in 4×4 grids.
3. Next, AES sequentially shifts the rows of “puzzle pieces” across every grid by one, starting with the second row. Here’s what it would look like:

1234

2341

3412

4312

1. The algorithm also uses a secret matrix multiplication formula with the private encryption key to swap around the pieces in each column. Here’s what it might look like with the shifted rows we used above:

4211

2434

1312

3342

1. Using the Rijndael S-Box chart and the new version of the grids it just created, AES then generates a unique “round key” for each grid. These round keys are created sequentially, based on the order of the grids that will be sent one after the other.
2. The algorithm then substitutes every “puzzle piece” in each grid with a different value based on the round keys.
3. Finally, it applies the XOR encryption cipher using the four columns in each grid and its designated round key to generate a new round key for the corresponding set of four columns in the next block. That means it would use column one in block one with that block’s round key to generate a new round key for the next block, and so on.
4. Based on the encryption strength, the algorithm will repeat steps 1-7 several times (except, step 4 is never repeated in the last round):

• • 128-bit encryption = 10 rounds
  • 192-bit encryption = 12 rounds
  • 256-bit encryption = 14 rounds

1. When a data packet reaches its destination safely, the recipient decrypts the first 4×4 grid of “puzzle pieces” using the shared symmetric key. Then it uses the shared key with that first grid’s round key to decipher the next grid, and so on, before piecing the whole data packet back into the completed puzzle again.

If anyone tried to build your puzzle without the right keys, in the correct sequence, they wouldn’t stand a chance. The pieces wouldn’t fit together or make a coherent image.

How Secure Is AES?

The most secure of them all! Snoopers would need to guess 2^256 unique combinations per data packet to decipher your data with 256-bit AES encryption, which is pretty much impossible with today’s technology. Even the lowest standard, 128-bit AES encryption, would still require 2^128 different combinations – which would take millions of years to crack, using the best technology available today. Even the military and government officials rely on AES encryption standards to protect their private communications. 

Certain VPN protocols use different types of encryption. For example, the OpenVPN protocol relies on 256-bit AES encryption, but WireGuard^Ⓡ uses ChaCha20 encryption. Both algorithms are incredibly secure, though ChaCha20 is generally more lightweight than AES encryption, which can help with better speeds.

What Is ChaCha20 Encryption?

ChaCha20 is a type of encryption algorithm. It still relies on 256-bit keys to encrypt your data, similar to the strongest AES encryption standard. Instead of sending your data in small, individually encrypted blocks as AES does, ChaCha20 transmits data in a continuous stream. This makes it faster and more lightweight than AES as there’s less delay between data packets. The WireGuard^Ⓡ protocol uses this encryption algorithm. It’s ideal for mobile devices because it balances security, speed, and required processing power.

What Are VPN Encryption Protocols?

So what do VPN encryption protocols have to do with this? A VPN encryption protocol determines how your device will communicate with the VPN server. Before any traffic leaves your device, the VPN establishes a secure tunnel using a VPN protocol. These protocols include sets of rules about how your data is secured and transferred. 

Most VPNs offer various protocols so you can choose one based on your activity or needs. Some protocols have greater speeds, so they’re better for things like streaming or gaming, while others offer extra security for more sensitive tasks. Some protocols are only supported by some devices. The most commonly used protocols today are OpenVPN and WireGuard^Ⓡ, though some VPNs still use some of the older protocols.

OpenVPN

OpenVPN is the most popular protocol. It’s open-source, so you can decide how to configure it yourself. Most VPNs offer OpenVPN built-in to the app so you don’t need to manually configure it to your device. It offers a good balance between speed and security, with AES 256-bit encryption to mask your traffic. It’s ideal for safeguarding your information, especially with online banking or while using public Wi-Fi where snoopers could be watching your every move. 

WireGuard^Ⓡ

WireGuard^Ⓡ is one of the newest VPN protocols. It relies on ChaCha20 encryption ciphers to transfer your data quickly and safely. This means you can get better speeds with WireGuard^Ⓡ compared to OpenVPN, as it relies on a less complicated cipher algorithm. It’s ideal for data-demanding activities such as streaming, gaming, or downloading files. 

Other VPN protocols

Some VPNs offer other protocols alongside OpenVPN and WireGuard, though these aren’t considered as secure or reliable as their two counterparts.

Protocol	Description
IKEv2/IPSec	IKEv2/IPSec has a built-in protocol that maintains a VPN connection when you move between networks, so it’s a popular choice for mobile connections. It’s still considered secure, but it’s not as fast as other protocols. It’s also only compatible with a select few devices.
L2TP/IPSec	L2TP doesn’t have any built-in encryption, so it’s combined with IPSec to keep your data more secure. It’s not particularly reliable for bypassing firewalls though, and it can significantly slow your speeds.
PPTP	PPTP has fast speeds, but that’s because the encryption is so poor. It’s not reliable for keeping your data secure, which could leave you vulnerable to leaks. Most firewalls also block PPTP so you’ll have trouble getting around restrictions.
SSTP	SSTP supports 256-bit AES encryption, so it was often the chosen protocol for secure browsing. It has shaky speeds though, and it’s very outdated. Most firewalls can detect and block SSTP traffic.

Secure Your Data with Advanced VPN Encryption

There you have it. VPN encryption can be tricky to understand, but it’s worth learning about. After all, it’s one of the most important features for keeping your data secure. Encryption blocks any outsiders from snooping on your information and helps to ensure your data doesn’t end up elsewhere, like in the hands of a cybercriminal.

You can download CyberGhost VPN to bolster your online security with advanced 256-bit AES encryption and VPN protocols. Our VPN keeps your private data securely locked away to make sure no one – and we mean no one – gets a look in. Not even us. An independent third party has audited our systems multiple times to confirm we’re sticking to our robust no-logs policy.

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