A few words about cryptography

We already know where the name comes from, so let me tell you how it all started. As early as ancient times, there was a need to share information and keep it safe from the wrong people. At first, it was enough to hide it, but it still posed a risk that an unauthorized person could find it. Therefore, hiding the content of the message seemed to be a better idea than hiding the message itself. People used two methods of cryptography. The first one involved changing the order of letters in sentences. A leather belt used in Sparta is a good example. The belt had a message written on it and it was wound around a bar of a particular thickness. This meant that a bar of the same thickness was necessary to read the message. The other method was the famous Caesar code. It substituted letters of the plain text with other letters or symbols. The cipher was based on replacing each letter with a different one located three places further in the alphabet.

Pic.1 Ceasar cipher example

Of course, since then, the ways we use cryptography have improved a lot. We could discuss the myriad of methods that have emerged from ancient times to the present. However, this is not the purpose of this article.

Cryptography today

Nowadays, we can distinguish between symmetric, asymmetric, and hybrid cryptography. The main difference is the way we use keys – strings of information in the form of bits that encrypt and decrypt messages. Even though it’s a major simplification, we can assume that the longer the key, the more effective the encryption.

• The first type, symmetric cryptography, uses an identical key for encryption and decryption. We can break such a message into blocks of 64 or 128 bits or a stream.
• The second type of algorithm is asymmetric cryptography. It uses the public key of the person to whom the message is sent. This person uses the private key to decrypt the message. Another difference between these two algorithms is the need to use complex operations.
• Hybrid encryption, the third type, combines different encryption methods. It uses both asymmetric and symmetric encryption elements to take advantage of each.

Unfortunately, despite the security measures, hackers attack quite frequently. They have both extensive knowledge and professional equipment. To increase security, we can use (among other things) authorization and authentication.

• Authorization – the control of who has access to information. It is based on user identification methods.
• Authentication is the verification of the identity of a given person, for example, through a log system.

Modern cryptography is extremely complex and technologically advanced. Nevertheless, we encounter it every day, for example, when finalizing banking transactions. Even though the first cryptographic methods are very old, some of them are still used today in a modernized form, for example, the Caesar cipher I mentioned earlier. The ways that allow us to share confidential information are constantly evolving. New solutions have only one goal – to maximize the level of data security.