##### The most important and interesting about encryption.

###### A series of articles understandable even to non-specialists.

Many a man associate encryption with military intelligence or the search for ancient treasures following mysterious notes. But in fact, encryption has long been our daily life. Every day we sit in front of computers, use electronic payments, VPN services, instant messengers, digital signature, etc. Encryption is used to exchange data between your computer and sites, to protect payment information, corporate information, personal data, emails, and to ensure secure messaging.

We should also mention the blockchain technology and cryptocurrencies. For these new phenomena of modernity, encryption is the basis of everything. If you are interested in, what is the difference between symmetric and asymmetric encryption, who are Alice and Bob, the meaning of the abbreviations DES, AES, RSA, etc., you will learn about this from our series of articles. In the first part, we will give a general idea of encryption and its key features.

So, **encryption** is two interrelated processes: the process of converting the original data into encrypted data (encryption) and the reverse process of bringing the encrypted data back to its original state (decryption).

Encryption is performed following to certain rules, according to which the original data is encrypted and decrypted. These rules are called **encryption algorithms**.

Encryption algorithms can be very simple: writing words backward, adding extra characters, writing numbers corresponding to certain letters of the alphabet. There are also more complex algorithms that were used many centuries ago: the shift of letters (“Caesar cipher”,”Cardan Grille”), etc.

Modern encryption algorithms are incomparably more complicated because they are based on complex operations and mathematical calculations. These calculations are impossible to understand without deep knowledge of higher mathematics.

The key is the main element of encryption. The key is a unique secret element on which the results of the encryption algorithm depend. Imagine a room with a code lock. The lock design and its ability to open and close the door is an encryption algorithm. The code with which you can close/open the door to the room is a key, unique and secret. The lock is always the same and always works the same way, but the code can be changed.

All modern encryption algorithms have such property as “**strong cryptography**” – the ability of the encryption algorithm to resist cryptographic analysis, the purpose of which is to decrypt encrypted data without having a key to decrypt. Simply put, cryptographic strength reflects how easy or difficult it is to “crack” the encryption algorithm and fit the keys to encrypt/decrypt messages. In modern encryption algorithms, the key is measured in bits. The “longer” the key, the stronger the cryptography of the algorithm, so long key is considered more secure, i.e., resistant.

In connection with the cryptographic strength, there is a sustainable definition in cryptography – “**brute force attack**“. This is the exhaustive search of all possible variants of keys. The more computing power and time required to iterate all the variants of a key to decrypt the original data, the more the encryption algorithm is considered to be robust.

And now let’s talk about Alice, Bob and Eve (Alice, Bob, Eve), who are often mentioned when we are talking about encryption. These are the fictional heros of cryptography, invented by the American cryptography specialist Ronald River in 1978. Alice and Bob symbolize people, devices, computer programs, that is, any objects that want to exchange secret messages. Eve (“eavesdropper”) is someone who wants to intercept messages and read them.