Playfair密码（英文：Playfair cipher 或 Playfair square）是一种替换密码，1854年由查尔斯• 惠斯通（Charles Wheatstone）的英国人发明。-Playfair password (English: Playfair cipher or Playfair square) is a substitution cipher, invented in 1854 by Englishman Charles Wheatstone (Charle

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 substit