Basic application of mathematics in cryptography

As an interdisciplinary subject, cryptography involves a wide range of disciplines, of which applied mathematics account for a large proportion, and its status are also becoming more and more important in cryptography. Importantly, this article briefly introduces the basic theory and application of various algorithms involved in mathematical theory and method calculation in cryptography, and divides the development history of cryptography into modern cryptography and traditional cryptography, enumerating the two representative plaintext encryption methods, and summarizing one of them respectively and elaborately.