Encryption is used by VPNs to keep users’ traffic safe from any online snoopers, meaning hackers and ISPs but also governments or other corporate entities. When establishing a connection to a VPN server, the tunnel through which the information travels applies an encryption and makes it impossible for anyone to decrypt it without a corresponding key. In turn, both end points in a connection – the sender and the recipient – have access to that key, which is the responsibility of the VPN and is different for every user and for every connection.
However, explaining VPN encryption is no simple task. This is one of the most complex components of a VPN and it’s also impossible to understand without also being aware of other parts of the encryption process, such as VPN protocols, ciphers, RSA handshakes and algorithms.
First things first, it’s important to know about different VPN protocols, which each have their own pros and cons. These protocols apply different encryption levels to make a VPN connection either more or less safe, which as a result affects the overall speed of a connection. These levels are dictated by the type of encryption used, with Blowfish, IPSec, AES-128 and AES-256 being some of the most popular options. In fact, AES-256 is considered to be unbreakable to this date and is used by the U.S. government and military to encrypt its communications – so it’s the preferred choice for a VPN connection when speed is not an important factor. However, if speed is a concern, then AES-128 is a reliable choice as it eases a little on the encryption’s strength but is still solid and very unlikely to be broken.
As our guide explains in further detail, the binary key length plays an important role here. Binary code consists in either numbers 0 or 1 and if each bit of data has these two possible values, then a key with 128 binary digits (128-bit) can have 2,128 possible combinations, which would take something like 1,022 years to check every possible key. Consider 256-bit keys, then, and the result is the impenetrable encryption that is most commonly used by VPN providers.
When it comes to the actual encryption keys, try visiting aesencryption.net. This free online encryption tool lets you encrypt a sentence using whatever keys and key lengths you desire, resulting in complete gibberish that can only be translated with access to this key. You’ll notice that the smallest of changes in the key alters the results drastically. This happens because in the sentence all the letters were replaced with numbers, symbols or other letters – for example A = L, B = F, C =P. This is the same concept behind VPNs, only on a much stronger and more complex scale.
As such, the encryption key is automatically applied to each user’s VPN connection and because of the secure method of communication – termed RSA handshakes – the key is different every time, even when connecting to the same servers. ISPs and hackers don’t have access to the decryption key, so even if they were able to intercept traffic they would only see the unintelligible text and will be unable to decrypt it.
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