熟悉java平台开发环境；

理解常见古典加密算法：恺撒密码、多字母替代密码、多表替代密码；

理解古典加密技术中的替换技术、置换技术。

-Familiar with the Java platform development environment

Understand the common classical encryption algorithm: Caesar cipher, substitution cipher letters, multi-table substitution cipher

Understand the technology of the classical encryption technology replacement, replacement technology.