Test.java：总测试程序。
AESHelper.java：AES加解密工具。
DESedeHelper.java：3DES加解密工具。
RSAHelper.java：RSA加解密工具。
SignatureHelper.java：MD5, SHA-1签名工具。
Base64.java及Hex.java：字符串与字节码转换工具。
Base64如报错，请用security中的jar文件换掉JRE/lib/security中的jar包。
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