You're sitting in the laundrette waiting for your laundry and suddenly see a sign with Wi-Fi access details. You don't hesitate for long and connect to the laundrette's public Wi-Fi. Here I explain why this might not be the best idea and what you should do instead.
No privacy on public networks
Public Wi-Fi is for everyone, because anyone can connect, be it a customer of the laundrette or a hacker. And a hacker can then spy on data by infiltrating between the router and your device. This is possible because most public networks use no or only weak encryption because they use outdated protocols. This allows a hacker to access bank details or other personal information.
VPN - the solution?
To surf securely on a public network, a VPN should always be used. VPN stands for "Virtual Private Network". "Virtual" because the connection is not physical, and "private" because it is an encrypted connection. But what exactly is a VPN?
Put simply, a VPN establishes a secure connection with a server in a remote network. The remote network can be the network of a company or the network of a VPN provider. The data is then forwarded from this network to its destination. The two key features of VPNs are firstly encryption, as a VPN only transmits data in encrypted form, and secondly the concealment of your IP address. But more on this later.
Example
Let's take a detailed example: You are in a public WLAN and connect to a VPN. All messages are first sent to the server, also known as the VPN server, in the VPN provider's network or in the company network and from there forwarded to the recipient.
The task of the VPN server is to receive the message from the sender, convert the sender's IP address into its own IP address and then transmit the message to the recipient. With this method, it is possible that the recipient does not see your IP address and therefore cannot recognize your location. When you reply, the connection runs in reverse order, i.e. first to the VPN server and then back to the original sender. Of course, all data traffic is encrypted at all times.
Advantages and disadvantages
A VPN has the great advantage that it protects you from being spied on or attacked in public WLANs by encrypting the data traffic, making it difficult for hackers to read the data. Also, as mentioned above, the IP address is hidden so that the recipient cannot see who the message originally came from.
Another advantage is that geographical restrictions can be circumvented. A VPN allows you to access media content from other countries that you would otherwise not have access to. For example: a series is only available on a streaming service in Spain while you are in Germany. Then you can simply use a VPN and connect to a VPN server in Spain.
In addition to the advantages, there are also disadvantages: For one, absolute security is not guaranteed, as sometimes it is not clear which encryption method is used by the VPN provider. Although other people cannot see your IP address or private data, the VPN provider can. This raises the question of how much you can trust the provider.
On the other hand, the internet speed via VPN is sometimes slower. This occurs because the data is first forwarded to the VPN provider and then from there. In addition, some countries block the use of VPNs so that they cannot be used there.
How does it work technically?
In a nutshell, a VPN uses the "IP packet in an IP packet" method. But let's explain this in more detail: We have a packet. This packet contains the actual message, a sender IP address and a recipient IP address.
Let's now go through what happens step by step:
Before the packet is sent, it is first completely encrypted and the recipient IP address is changed to the IP address of the VPN server. The sender IP address remains the same. The packet is then sent to the router in the network. The router converts the sender IP address into a public IP address, i.e. that of the router.
The packet is then sent to the server in the VPN provider's network. The packet is decrypted there. The IP address of the actual recipient of the message can then be seen in the decrypted packet. The VPN server now takes the decrypted message, the recipient IP address and its own IP address as the new sender IP address and forwards the message to the recipient
As we have seen in the article above, using a VPN is not a bad idea. Although there are disadvantages and you have to trust the VPN provider, the advantages clearly outweigh the disadvantages. Privacy protection is very important, especially if it's not your own network, but a public one with an unknown owner.
