利用RSA对称算法实现文件加密，密钥512位，比较安全。但不是特别安全。因为推荐2048位的密钥目前是很安全的。-use RSA asymmetric encryption algorithm document, the key 512, relatively safe. But it is not particularly safe. Since 2048 recommended the key now is very safe.

恺撒密码的实现源代码 恺撒密码是一种对称密钥算法 希望对大家有用,特别是学生-Caesar password achieve Caesar source code is a symmetric key algorithm hope useful for all, particularly students