What Is VPN Encryption? How It Works and Why You Need It

VPN encryption scrambles your online data as it travels across the internet, making sure no one can read it except you and the recipient. Even if someone were to intercept your connection, all they’d see is a random jumble of letters, numbers, and symbols. This is important for your privacy because it makes it harder for third parties to monitor or track your online activity. Even your ISP and network admins will no longer be able to see details about what you do on the internet, including the websites you visit.

But how exactly does VPN encryption work? What are the different types, and which one should you look out for when you’re choosing a VPN? Let’s take an in-depth look, from a step-by-step guide to the encryption process, to the different encryption methods and protocols available.

How Does VPN Encryption Work?

When you use the internet, your traffic travels in small units called data packets. These packets contain pieces of the information you’re sending or receiving. Unless encrypted, data packets travel through the internet as plaintext. This means if someone intercepts your traffic, they can see what you’re doing online. 

VPN encryption works by creating a secure tunnel for your connection. This is like a hidden highway that your data can use instead of traveling across the public internet. Before it enters the tunnel, your data is also scrambled into unreadable code so it can be safely sent back and forth. Lastly, your whole connection is routed through a private VPN server in a different location, hiding your real IP address behind one from the VPN’s server instead.

 Here’s what the VPN does from start to finish:

1. Secures the connection: Your VPN app communicates with a private server using a VPN protocol. The protocol decides which encryption cipher (algorithm for scrambling data) to use. 
2. Creates a shared symmetric key: The server and your VPN app generate a shared symmetric key to lock and unlock data inside the tunnel.
3. Encrypts your data before it leaves your device: The VPN app splits your data into packets and scrambles each one using an encryption cipher. This turns readable data into unreadable ciphertext.
4. Hides your activity from your ISP: Your encrypted data travels through your ISP’s network, but stays inside the VPN tunnel. Your ISP can see you’re connected to a VPN, but can no longer see which domains you visit.
5. Changes your IP address: The VPN swaps your real IP with the VPN server’s, so your traffic looks like it comes from the server instead of your device.
6. Decrypts and forwards your data at the server: Your data reaches the VPN server, where it’s decrypted by the shared key and forwarded to the internet.
7. Reverses the process for incoming data: Websites you visit send data back, the VPN server encrypts it, and sends it through the tunnel to your device. Your VPN app decrypts it using the same symmetric key.
   

Symmetric and Asymmetric Encryption

VPNs use both symmetric and asymmetric encryption. First, they set up a secure connection using asymmetric encryption, then switch to symmetric encryption to protect your data as it travels. 

Asymmetric Encryption 

When your device connects to a VPN server, the VPN app starts a process called a handshake. This is a negotiation about how to secure the connection. Both your device and the server have two keys: a public key and a private key. They swap public keys and combine them with their private keys to create a one-time session key. The session key can lock and unlock data during the connection. Even if someone intercepted the exchange and got hold of the public keys, they couldn’t recreate the session key without the private keys. Since there are two different keys (public and private), this type of encryption is called asymmetric.

Symmetric Encryption 

Once the handshake is finished, symmetric encryption takes over. It uses the shared key created during the handshake to scramble your data before it travels through the VPN tunnel. That way, both your VPN app and the VPN server can encrypt and decrypt the connection for the whole session. Since it uses the same shared key, this type of encryption is called symmetric.

Perfect Forward Secrecy (PFS)

Perfect Forward Secrecy is an additional security feature that can be added to make encryption even safer. It creates a fresh, temporary key for every session, and sometimes updates it while you’re still connected. Even if someone managed to get one key, which is extremely unlikely, they’d only be able to decrypt a small amount of data, and couldn’t access past sessions.

Different VPN Encryption Types

Not all VPN encryption is the same. The cipher your VPN uses affects the speed and security of your connection. Here are the most common ones you’ll come across.

AES Encryption

Most reputable VPNs use AES (Advanced Encryption Standard). AES is a symmetric block cipher, which means it encrypts data in fixed chunks instead of per bit (the smallest unit of data) or byte (8 bits). This makes encryption efficient because lots of data can be encrypted at once. 

AES is also very secure because it uses large keys (usually made up of 128 bits or 256 bits) that are essentially impossible to crack. 128-bit AES encryption can be faster, since the keys are smaller, so encryption and decryption are quicker. However, 256-bit encryption is much more secure. CyberGhost VPN uses AES 256, as do high-security institutions like banks and governments.

Camellia

Camellia is another block cipher like AES. They were developed around the same time, but AES has since become the global standard. Most modern devices have AES support built in, but Camellia can sometimes be more efficient than AES on older systems that don’t have this integration. 

ChaCha20 Encryption

ChaCha20 is a stream cipher, which means it encrypts data one byte at a time. This makes it good for activities that need low-latency connections, like streaming or video conferencing. That’s because each byte is encrypted and sent as it arrives, allowing information to travel faster in real-time. 

Many trusted VPN providers support ChaCha20 because it’s lightweight, fast, and very secure. WireGuard® uses this cipher, and it works well for mobile devices or other systems with less processing power.

VPN Encryption Protocols

VPN protocols are the rules your VPN follows to secure your connection. They determine how your data is protected and sent. Here are the most common protocols:

• • OpenVPN: This widely used protocol is open-source, which makes it both flexible and trustworthy. It uses AES-256 encryption and offers a good balance between speed and security.
  • WireGuard®: This newer protocol is built to be lightweight. It only has about 4,000 lines of code (compared to 70,000+ in OpenVPN or 400,000+ in IPsec). It’s super fast, but it isn’t always compatible with older devices.
  • IKEv2/IPSec: This stable protocol keeps your connection steady when you switch networks. That makes it a great choice for mobile devices that regularly need to switch between Wi-Fi and cell data.

Other VPN Protocols

Protocol	Description
L2TP/IPSec	L2TP doesn’t encrypt data on its own, so it’s paired with IPSec for security. It’s safe but slower than newer options and often gets blocked by firewalls. Today, it’s mainly a backup when better protocols aren’t available.
SSTP	SSTP supports 256-bit AES encryption, but it’s slower and less efficient than newer protocols. It’s good at bypassing firewalls, though, so it’s often used as a backup for particularly restrictive networks.
PPTP	PPTP is an obsolete protocol that’s no longer recommended because it’s considered insecure.

Why Use a VPN to Encrypt Your Traffic?

1. Avoid ISP tracking: Your ISP can see some details about what you do online, including the sites you access. VPN encryption hides this information inside the VPN’s secure tunnel. Your ISP can see you’re using a VPN, but they can’t see the domain names you visit.
2. Stay safe on public Wi-Fi: Open hotspots are unsecured, so anyone can join. This makes them vulnerable to cybercriminals, who might try to hijack your connection. If you’re connected to a VPN, the encryption makes sure any potential snoops only see scrambled data instead of sensitive information.
3. Prevent ISP throttling: ISPs sometimes slow down (throttle) your internet connection during data-heavy activities like streaming or throttling to preserve bandwidth. They use a few methods to detect your activity, including checking the site you’re using. VPNs can’t help with every kind of detection, but they can stop your ISP from throttling you whenever you visit a streaming site, for example.
4. Overcoming network blocks: Schools and workplaces may block access to certain websites to promote productivity. Since it sends all your traffic through an encrypted tunnel, a VPN stops local networks from seeing which sites you’re accessing, so they can’t block you.

Encrypt Your Internet Connection

VPN encryption gives you enhanced security and privacy online. It wards off snoops who might try to track and monitor your internet activity, and it adds protection from cybercriminals who might want to steal your data. 

That said, you also need to choose a VPN that offers strong encryption and the safest protocols. CyberGhost VPN uses 256-bit AES encryption to secure every connection. It also supports fast, safe protocols, including OpenVPN and WireGuard®. Test it out for yourself risk-free with the 45-day money-back guarantee. 

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