What is encryption and why do you need it?

How does it work?

There are currently two types of encryption: symmetric and asymmetric. Each has its advantages and disadvantages and each is used for different purposes. They differ in the way the encryption key is distributed. Using the analogy of a mailbox, the way they work can be described as follows:

Symmetric encryption uses the same key to encrypt and decrypt data, so anyone who comes into possession of the key can open the mailbox and read the message, or even modify it without the sender or recipient knowing. It’s much more efficient and is therefore used for solutions where large amounts of data need to be encrypted. The best-known standard is AES. Due to the problem of key distribution (anyone who has it can view the data), it’s not likely to be used for mass solutions, but only where access to data is restricted to a small group of people.

Asymmetric encryption uses a pair of keys – public and private. The public key is only used for locking the mailbox (encryption), and you can give a copy of it to anyone who wants to drop a message for you into the mailbox. However, only you can open it (decrypt the data) with your private key which you don’t share with anyone and keep in a safe place. For this reason, although it requires more computing power, it’s a popular solution for mass communication (e-mail or messengers such as WhatsApp or Signal). The only (as of now) way to decrypt such messages is to get hold of the private key, which actually means taking control of your device, i.e. stealing it.

How to use encryption?

Thankfully, you usually don't have to do anything because the ISPs do it for you. :) Any website with an SSL certificate (the small padlock symbol to the left of the address) encrypts all the data you enter on it. Remember, however, that the mere presence of an SSL certificate does not prove that you are giving your data to a trusted company (we look at this in more detail in our article about secure logging onto websites). Providers of the most popular e-mail services or instant messengers also ensure end-to-end encryption, i.e. from the sender's device to the recipient's device – also for video and voice calls.

Having said that, if this is not enough for you and you are still worried that someone may "eavesdrop" on your data, you can use a VPN (virtual private network) service – a solution that directs all network traffic from your device to an encrypted "tunnel" through which it reaches its destination without the possibility of decryption along the way. There are many solutions of this type available on the market – both commercial and free. Some antivirus vendors offer VPNs as part of their computer security packages.