Data encryption is nowadays the most effective way to protect data against any external threats. This process, not very aptly, can be compared to locking the data in a safe, where a special key is needed to pull them out.
Encryption is based on the algorithm to which the key is generated. This happens when a connection is established between two computers. Cipher used in cryptology is a parameterized code used to transform the data to be illegible and almost impossible to read for a person who does not have the appropriate key. Before encryption we have plaintext, and after encryption we get a ciphertext. Sometimes in Polish literature one can find terms such as "clergy" and "clarinet", which refer to the words "clear" and "crypt", and references were made by people using the so-called "ponglisz", i.e. a very practical mixture of Polish and English.
In practice, three types of ciphers, or rather groups of ciphers, are used today. These are asymmetric, symmetric block and symmetric streaming ciphers. The most common asymmetric codes use two keys: public and private. The first one is used to encrypt the message and the second one to decrypt it. Private keys are always stored only on the customer's computer, so there is no risk of being intercepted. They use interesting mathematical properties, where reversal of simple issues can be very difficult. For example, multiplication is much easier than dividing the result into all factors. In almost equally widely used symmetric block ciphers, extremely simple mathematical operations are used to transform data by, for example, adding a constant value to the data. This is done on small blocks of data, but due to the fact that it is not known what specific transformations were carried out successively, several subsequent mathematical operations cannot be traced in practice.