How Is VPN Encryption Done? What plants may I choose?

How Is VPN Encryption Done? What plants may I choose?
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Here, we discuss the various forms of VPN encryption, how they operate, and what to look for in a good VPN service provider.

In order to keep your personal information safe, virtual private networks (VPNs) encrypt your data. Learn about the three main types of encryption used by the vast majority of VPN services, and why so many different algorithms are needed.

A virtual private network (VPN) protects your internet traffic from being read, intercepted, altered, blocked, or substituted by third parties. Achieving these goals requires hiding all data and connection settings transferred between your computer and the servers it communicates with on the internet. By using encryption, this is made possible.

How Is VPN Encryption Done? What plants may I choose?

VPNs must use three different types of encryption because of the multiple attack routes that can compromise your communications. The following are among them:

Asymmetric encryption protects data in transit, while public-key encryption allows encryption keys for data routes to be released publicly.

Hashing ensures data integrity.

This post explains how VPNs use these three types of security and how they work... OpenVPN is the most secure VPN technology available today. Developers can utilize this set of functions to embed whole security protocols into VPN applications. You won't be able to hide any secret surveillance methods using this method because it is open source. A look at the encryption methods used by OpenVPN will be covered in this section.

Symmetry-based cryptography

The oldest sort of cipher in use today is the asymmetric one. A method of code translation that dates back to the Roman era is at the heart of this system. Data is transformed by an algorithm. The outcome of the encryption can be affected by one of the algorithm's variables. The "key" is what we call it.

In order to decode encrypted text, the same substitution mapping must be used for both encoding and decoding. Because both sides use the same key, it's referred to as symmetric. The term "shared key" or "shared secret" is frequently used to describe this type of encryption.

Symmetric ciphers of the present-day go well beyond a simple technique of code shift. Grid-based text grouping is one of these algorithms' most challenging methods. The key block shifts scramble, and swaps the contents of each grid in a variety of ways, depending on the parameters of the encryption scheme. VPNs commonly employ this type of symmetrical key encryption algorithm, known as a block cipher.

The most common ciphers used to encrypt VPN data are the following:



Detailed information about these ciphers can be found here.


When the Advanced Encryption Standard (AES) was developed, it was by two Belgian cryptologists, Vincent Ramjan and Joan Daemen. Encryption known as Rijndael, which the two had previously invented, was modified to create AES by the duo. NIST, the United States' national standards agency, identified AES as a critical need (NIST). Developing a secure encryption system for the US government and its various agencies was the mandate of the Institute.

As far as VPNs are concerned, this is the best option because it's universally accepted by the authorities. Those who are opposed to AES often question the system's integrity because of the changes it has undergone to fulfill US government specifications. It's been suggested that a backdoor was included into AES that would allow the authorities to listen in on users' private talks. However, despite several recent leaks by the secret agency, no evidence of the existence of this backdoor has been revealed.

AES is a block encryption algorithm that uses 128-bit arrays to encrypt data streams (16 bytes). The length of the key might range from 128 bits to 192 bits to 256 bits. In each block, there is a 4-by-4-byte grid. The length of the key influences the number of transformations:

The 128-bit key for 10 rounds

12-cycle key exchange, with 192-bit encryption

A 256-bit key was used for 14 rounds.

Bitwise xor with the key, substitution, row shift and column mixing are all part of the transformation cycle.

AES is used by virtually every major VPN service, including ExpressVPN, NordVPN, CyberGhost, IPVanish, PrivateVPN, Surfshark, VyprVPN, ZenMate, PureVPN, StrongVPN, VPNArea, SaferVPN, Ivacy, GooseVPN, Windscribe, and HideMyAss.


Concerns have been raised about the US government's involvement in AES. Blowfish was favored by some who doubted the security of the Advanced Encryption Standard.

Blowfish is OpenVPN's default cipher for data security. VPNs generally prefer AES to Blowfish since it is faster.

As a replacement for AES, VPN companies used Blowfish, which is more secure. The cipher's creator, Bruce Schneier, deliberately did not patent the technique, allowing anyone to use it for free. The fact that it is part of the open-source and free OpenVPN system speaks much about its usefulness.

Compared to AES, this block cipher uses a smaller array. In comparison to the AES grid, it uses a 64-bit block. To put it another way, the system is far less safe than AES. As an anti-establishment supplement to AES, the Blowfish cipher served its objective. However, the small block size makes it vulnerable. VPN providers do not support Blowfish presently. As of this writing, both Buffer and PrivateInternetAccess have converted to AES encryption.

Blowfish's creator, Bruce Schneier, is now encouraging the public to avoid it in favor of Twofish, its replacement. There have been no large VPN providers, however, that have followed this advice. Former Blowfish users have made the move to AES. If you're in the market for a VPN, be sure it uses AES encryption, because no credible VPN service will use anything less.

Using public keys to encrypt data

Your data exchanges are protected to the fullest degree possible with AES encryption. Why would a VPN need a different sort of encryption, then?

The need that both parties to a data transmission share the same key is an obvious security weakness in symmetric encryption systems. To establish a connection, your VPN client, if it has one, will have to send one of its AES encryption keys to the chosen VPN server. VPN companies, on the other hand, are more efficient if they produce their own encryption keys. It is a security risk, however, since the client is tough to execute on your device.

No matter how secure symmetric key encryption systems are, an interceptor can decrypt any encrypted messages if the key is obtained by the interceptor. The VPN's ability to function properly depends on the distribution of keys being protected. The transmission of keys poses a security risk, although this is mitigated by using public-key encryption.

In public-key encryption systems, the key used to decrypt a communication is separate from the key used to encrypt it. Since decryption keys cannot be deduced from an encryption key, there is no risk in revealing the encryption key to the public. "Encryption approach" is derived from this. The encryption key is made public, while the decryption key is kept private...

Public-key encryption is used by VPNs to encrypt AES key transfers. It is encrypted using the VPN client's public key by the server and then sent to the client through a secure connection. The communication is then decrypted by your computer's client program using a private key that only it has access to.

When you click the Connect button in the VPN interface on your computer or phone, AES keys are transferred. The first step in establishing a secure connection is the creation of a session, which includes a range of security measures. Transport Layer Security (TLS) is a system that combines all of these approaches.

Transport Layer Security

It is impossible for interceptors to pretend to be the true correspondent of a connection while using TLS as an authentication protocol.

TLS isn't simply for virtual private networks (VPNs). Most websites utilize it to keep their data safe, which is why it has become so popular. TLS is activated if the URL begins with HTTPS:// rather than HTTP:// in the address bar.

A forerunner to TLS is the Secure Sockets Layer (SSL) (SSL). As a pioneer in the field of web browser development, Netscape Corporation released the first version of this in 1995. Due to security flaws discovered in SSL, SSL was phased down in 1999/2000 and HTTPS was introduced in 1995.

If a computer wants to communicate with another over the internet, it must first obtain that computer's public key. However, the server's key is not expressly requested. As an alternative, the client uses a third-party database to perform a search. Several unique properties of the target are included in the security certificate returned by this query. In addition, the server's public key is included.

Interceptors can no longer pretend to be the intended recipient thanks to the TLS protocol. If a client sends an encrypted message to a server, an interceptor will be unable to decrypt the message and return a legitimate response. This step is called a "challenge" because it guards against the "man in the middle assault" that hackers use.

VPNs commonly use TLS since OpenVPN's library contains the essential methods. OpenSSL is another open-source security library that is used in OpenVPN. The package's name suggests SSL, but it actually implements TLS. On the internet, SSL and TLS are usually interchangeable terms. TLS is commonly referred to as SSL by the vast majority of networking professionals.


For public-key encryption, there is no better choice than the widely used RSA algorithm. Founded by Ron Rivest, Adi Shamir, and Leonard Adleman, this moniker is taken from their initials. SSL, HTTPS, and much of the internet were not invented until 1977 when this encryption was first used.

A two-prime private key is used to encrypt the message. The private key's prime numbers are related to the public key's length. RSA public keys are typically 1024 bits, 2048 bits, or 4096 bits long.

The mathematical procedures required to perform encryption and decryption are simple. Because of this, data is not rearranged into blocks like it is in the AES system. In spite of its ease of use and seeming speed, RSA is a cumbersome process that would impede data transit if used during the session. Together with its inclusion in TLS, this means that only session establishment procedures are performed using RSA, not VPN data encryption. "

In some cases, VPNs use RSA to both authenticate and encrypt AES keys while they are in transit. ZenMate is a VPN service that falls under this category.


It was released in 1976, making it a little older than RSA, a public-key cryptographic algorithm. Whitfield Diffie and Martin Hellman founded the company. RSA-like encryption algorithms are employed in this system.

A "shared secret" is a combination of a public key and a private key that is generated as a result of communication between the parties involved in a connection.

Many VPNs use the Diffie-Hellman mechanism to distribute AES keys because it is embedded into TLS operations and is included in the OpenSSL package that comes with OpenVPN. Diffie-Hellman is used by HideMyAss, while other major VPN companies use a variant known as DHE.

To describe this situation, we use the term "static-ephemeral," in which the server's certificate value is "static" and the client's randomly generated key contributions are "ephemeral." This is how Diffie-Hellman (DH) works. It is called "ephemeral-ephemeral," or Diffie-Hellman Ephemeral because the key-value contribution from the server is also a random number.

Hashes are computed using algorithms.

Hashing is a third encryption method employed by VPNs. "SHA" appears numerous times in VPN specifications. They use this algorithm for hashing. The term "Secure Hash Algorithm" is referred to by this acronym.

While in transit, data is encrypted using this method to ensure its integrity and to confirm that it came from the reported source. Classified as "hash message authentication code," the SHA algorithm (HMAC).

TLS and the OpenSSL library used by VPNs include SHA. The hashing process does not take place via a virtual private network (VPN). It's utilized in the certificate retrieval process to make sure the certificate data wasn't delivered by an interceptor but rather the certifying authority. The fabrication of certificate data was the primary flaw of SSL that motivated the migration to TLS. RSA public key exchange is possible if an interceptor can provide his own certificate in response to a VPN client's request for it.

There are a lot of different varieties of SHA, as you would have guessed. The SHA-1, SHA-2, and SHA-3 algorithms are known as such. Vulnerabilities in SHA-1 have been found. Large numbers of transactions during a secure session can lead to problems with this strategy when combined with HTTPS. Using this method to protect the transfer of certificate information reduces the vulnerability of VPNs, as it is a one-time usage that does not give hackers enough time to breach security. In contrast, the most popular VPN services use SHA-2 and SHA-3 instead. Of the three, SHA-2 is by far the most popular.

Different block sizes are used for different SHA-2 variations. There are also a number of condensed variations. This is why you won't see the term "SHA-2" in the VPN specification because the SHA-2 variants have different widths. Instead, the most common SHA-256, SHA-384, and SHA-512 variations are found.

Security hashing algorithm SHA-2 is used by a number of VPNs, including CyberGhost and PrivateVPN as well as VyprVPN and ZenMate. However, NordVPN utilizes the SHA-384 algorithm whereas ExpressVPN, IPVanish, Surfshark, and StrongVPN use the SHA-512 algorithm.

key's length in bytes

Due to the one-phase nature of RSA's encryption mechanism, it requires a key that is far longer than the standard AES key to assure its security. A 1024-bit RSA key, compared to AES's maximum 256-bit key, appears excessively long. However, this RSA key length is no longer considered safe.

Most VPNs use RSA keys with a length of 2048 bits or more. Following reports that Chinese officials had cracked ExpressVPN's 1024-bit RSA encryption key, the company upgraded to a 4096-bit key in 2016. CyberGhost quickly followed suit, as did TorrentFreak. RSA keys with a 1024-bit key size are no longer used by any reputable VPN operator.

It's easy to get confused by the varying key sizes required by various encryption algorithms. The National Institute of Standards and Technology (NIST) has created a cipher classification system that takes into account the various "security strengths." Table 2 in NIST's Recommendation for Key Management, Part 1, has been condensed into the following form.

A unique identifier is assigned to each item. There are two tables with the same ID number.

The AES formula's relative strength can be better appreciated with the help of these length crucial equivalences.

Some VPN companies enable shorter keys, while others use shorter keys in their mobile apps and browser extensions. While all major VPN providers provide AES with a 256-bit key, To give an example, NordVPN's desktop apps use AES-256, while its browser extension uses AES-128; PrivateVPN customers can select between a 128-bit and 256-bit AES key when using the VPN service, for example.

Using a longer key necessitates more encryption cycles than using a shorter one. You'll need to use more processing power on your mobile device to perform this additional job, and it will take longer and drain your mobile device's battery faster. In spite of its minimum key size of 128 bits, AES has never been deciphered. "Uncrackable" is the only level of intractability that some cryptanalysts believe there is. That is why 128-bit AES keys are so secure.

Block Cipher's several modes

In addition to allowing you to set the key length for an AES connection, the VPN also lets you specify the block cipher mode, as shown in the screenshot from the PrivateVPN dashboard above. CBC and GCM are the two protocols available on the PrivateVPN dashboard.

Cipher Chaining

An abbreviation for Cipher Block Chaining is CBC. This approach strengthens encryption by XORing (exclusive OR) each block with the previous block. However, this improves the complexity of cracking the encryption, but it also slows down the encoding process, as the blocks cannot be processed in parallel. If you're looking for the most common technique to use a virtual private network (VPN), you'll most likely choose this method.

The Galois/Counter Mode of operation

It stands for Galois/Counter Mode and is a shorthand for both. In terms of efficiency, this is a more recent method than CBC. This system utilizes two different types of transformation. Counter mode is a transformation exercise that generates a pseudorandom number for each encrypted block. A counter in the calculation indicates the order of blocks, reducing the effect of the pseudo-random generator returning the same number repeatedly during block processing. Each session's counter is initialized with a unique value in order to avoid the dangers of numerical repetition.

The term's Galois component refers to the multiplication of the Galois field of each block. Mathematical operations can only be applied to a finite set of variables. That is to say, the block has a fixed size and is not open-ended.

The Galois Message Authentication Code hashing method is one of GCM's most notable features (GMAC). As a result, SHA is no longer necessary. One more benefit of using GMC over CBC is the ability to process blocks in parallel, resulting in significantly faster encryption times.

Virtual private network (VPN) encryption examples

In contrast to PrivateVPN, most firms only offer one combination of key length and block cipher mode as a basic service. We've rounded together some of the most popular VPN companies' encryption levels and modes of operation:

ExpressVPN employs AES-256-CBC for its encryption.

AES-256-CBC encryption is used by NordVPN (for Windows, macOS, and Android)

NordVPN utilizes AES-256-GCM for its encryption (for macOS and iOS)

CyberGhost uses AES-256-GCM.

IPVanish uses AES-256-CBC as its cryptography standard.

Surfshark uses AES-256-GCM.

In the case of VyprVPN, AES-256-CBC encryption is used.

An active key's duration, in addition to the kind of encryption and encryption mode, is an important consideration when evaluating a VPN service's security.

Perfect Transparency in the Future

An unauthorized decryption method commonly used by hackers and government snoopers is known as "brute force assault." Every possible combination of the key's characters must be attempted in order to find a working one. Cipher-deciphering techniques that are faster than others often depend on luck or the key's location.

Limiting the key's validity is a major strategy in preventing hackers from cracking encryption codes. An activation key can only be active for a limited amount of time using Perfect Forward Secrecy (PFS). Multiple connections within an organization are never established using keys. To make matters worse, keys can't be reused across several devices. A unique key is used for each link. A single key will be used for your initial connection and another will be used for all subsequent connections if you frequently login from a single location and then switch servers on a VPN server.

You can use the same key for a longer period of time if you keep your VPN connected at all times. Hackers can't break even the toughest encryption, like AES, even after long sessions.

Additional methods of VPN security

OpenVPN is the security backbone of every premium VPN service. In addition to OpenVPN, several VPN service providers also provide other VPN protocols. Applications may not be available for all of these systems. These other systems can usually be configured manually inside the operating system settings of your device in the majority of cases.

OpenVPN's key competitors include the following:


If you need the maximum level of security and privacy, you should not use any of these OpenVPN alternatives. It's possible that these solutions will satisfy your VPN needs in some cases.


The Point-to-Point Tunneling Protocol served as the foundation for the first VPN system. It was created by Microsoft and is included in all versions of Windows. Even while adding support for this protocol is simple for a VPN service, the vast majority of them do not bother to give their apps access to the operating system implementation. PPTP uses the Microsoft Point-to-Point Encryption (MPPE) method, which offers 40, 56, or 128-bit encryption keys. MS-CHAP v2 (Challenge-Handshake Authentication Protocol) is used to authenticate PPTP's authentication procedures.

VyprVPN is one of the few VPN services that support PPTP in its mobile app. A 128-bit key is used to encrypt the data, which can be changed manually. The PPTP protocol, which employs 128-bit key MPPE encryption, is also available in ExpressVPN's Windows client software. With an ExpressVPN subscription, you can also manually configure PPTP. Use the PrivateVPN software to get PPTP access. It is possible to manually configure PPTP on CyberGhost, IPVanish, and PureVPN.

PPTP is not a safe method of transferring data over the Internet. Its designers, Microsoft, have urged its discontinuation and created SSTP as a replacement.


Layer 2 Tunneling Protocol (L2TP) is considered antiquated and insufficiently secure, much like PPTP. NordVPN and Surfshark, for example, have opted to omit these two protocols from their offerings. By itself, L2TP does not offer encryption. In most cases, an IPsec system is used to do this. The majority of operating systems incorporate both of these protocols.

Session establishment through L2TP has been shown to be a significant source of security vulnerability. This is done by using a pre-shared key that can be determined easily.

A lower networking layer than that used by previous VPN solutions is where IPSec operates. Even if a packet is only one of a session's stream of packets, each transfer is handled as a separate transaction. There must be an authentication header (AH) prior to an encapsulating security payload (SPP) in order for this to work (ESP). For the original packet to be delivered, an ESP must be used to protect it.

Because L2TP is a slow protocol, it does not offer any advantages over more secure protocols in terms of performance. Because the NSA can break this VPN system, it's advisable to avoid it, according to Edward Snowden. L2TP is supported by many VPN services, including ExpressVPN (Windows, iOS, and Mac), PrivateVPN, IPVanish, CyberGhost (Android and iOS), and VyprVPN (Windows, iOS, and Mac). You can manually install L2TP on your device if you have a PureVPN or IPVanish subscription.


IKEv2 is far more secure than L2TP and is supported by the vast majority of VPN services. Internet Key Exchange is referred to as "IKE." Because IPsec is used to secure IKEv2, each packet is treated as a discrete transaction. If you're looking for an alternative to OpenVPN while utilizing a VPN on a mobile device, IKEv2 may be the best option. In comparison to OpenVPN implementations, this protocol uses less processing power and consumes less battery life. As with OpenVPN, IKEv2 uses a system of security certificates to verify the identity of its users. While the key exchange is also protected by the use of Diffie-Hellman encryption,

Users of ExpressVPN for iOS can use the app to establish an IKEv2 VPN connection. It is possible to connect to IPVanish's servers through IKEv2 on Mac and Windows, as well as on iOS. You can use IKEv2 with any of Surfshark's apps on any of these platforms. iOS and macOS use IKEv2 by default but Windows and Android can be made to use it. PureVPN's Windows and iOS apps offer IKEv2 as a connection option, while Android, Mac OS, and Blackberry devices can manually configure it as well. Manually configuring an IKEv2 connection is possible with VyprVPN and PrivateVPN services.


OpenVPN's secure counterpart, the Secure Socket Tunneling Protocol (SSTP), offers a more secure alternative. A Microsoft-owned proprietary system like PPTP is the successor to PPTP. OpenVPN's session establishment is secured via TLS, which is also used by that protocol. HTTPS relies on TLS as its primary security measure. Because this VPN protocol is proprietary, it has only one drawback: Microsoft was found to be providing the National Security Agency (NSA) with access to Skype calls and other communications data. Since Microsoft controls a lot of the encryption technology, security experts warn against using it.

Windows, Linux, and macOS all support this VPN protocol, however, mobile devices do not. PureVPN's Windows and Mac OS apps also support SSTP. SSTP is supported by StrongVPN's Windows client.

VPN encryption alternatives

In the search for a VPN provider, you should focus on those that support OpenVPN. This is, without a doubt, the safest protocol currently in existence. Search for services that support IKEv2 in their mobile apps if you frequently use the internet via mobile devices to avoid draining your battery.