Since the invention of the written word, there has been a need for confidential correspondence. Throughout history people have puzzled over the question: how to send a message to the addressee so that it could not be read by anyone else (in other words, how can one ensure data confidentiality)? Cryptography was born in an attempt to answer this question. Its roots go back to the very beginning of civilization - for example, special hieroglyphs for communication between monarchs were used in Ancient Egypt more than 4,000 years ago. Later, encryption techniques were improved and made more complex until at the end of the 20th century, when a revolution occurred; the invention of asymmetric encryption. But where does blockchain technology fit in in this new, rapidly changing reality? Let’s find out together.