using?System;
using?System.Text;
using?System.IO;
using?System.Security.Cryptography;

namespace?StudentManager
{
????///?

????///?字符串加密解密類
????///?

????public?sealed?class?StringSecurity
????{
????????private?StringSecurity（）?{?}

????????#region?DES?加密/解密

????????private?static?byte[]?key?=?ASCIIEncoding.ASCII.GetBytes（“uiertysd“）;
????????private?static?byte[]?iv?=?ASCIIEncoding.ASCII.GetBytes（“99008855“）;

????????///?

????????///?DES加密。
????????///?

????????///?輸入字符串。
????????///?加密后的字符串。
????????public?static?string?DESEncrypt（string?inputString）
????????{
????????????MemoryStream?ms?=?null;
????????????CryptoStream?cs?=?null;
????????????StreamWriter?sw?=?null;

????????????DESCryptoServiceProvider?des?=?new?DESCryptoServiceProvider（）;
????????????try
????????????{
????????????????ms?=?new?MemoryStream（）;
????????????????cs?=?new?CryptoStream（ms?des.CreateEncryptor（key?iv）?CryptoStreamMode.Write）;
????????????????sw?=?new?StreamWriter（cs）;
????????????????sw.Write（inputString）;
????????????????sw.Flush（）;
????????????????cs.FlushFinalBlock（）;
????????????????return?Conve