DES加密与解密：关键功能与应用示例

using System; 
using System.Security.Cryptography; 
using System.IO; 
using System.Text; 
using System.Globalization; 
  
  
/// <summary>  
/// 对指定内容进行DES加密和解密处理      
/// </summary>      
public sealed class DESEncrypt 
{ 
    /// <summary>      
    /// 对字符串进行DES加密   
    /// </summary>      
    /// <param name="sourcestring">待加密的字符串</param>   
    /// <param name="key">必须长度等于8的字符串</param> 
    /// <param name="iv">必须长度大于等于8的字符串</param> 
    /// <returns>加密后的BASE64编码的字符串</returns>      
    internal static string Encrypt(string src, string key, string iv) 
    { 
        byte[] byteKey = Encoding.Default.GetBytes(key); 
        byte[] byteIv = Encoding.Default.GetBytes(iv); 
        DESCryptoServiceProvider des = new DESCryptoServiceProvider(); 
        using (MemoryStream ms = new MemoryStream()) 
        { 
  
            try
            { 
                byte[] data = Encoding.Default.GetBytes(src); 

                using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byteKey, byteIv), CryptoStreamMode.Write)) 
                { 
                    cs.Write(data, 0, data.Length); 
                    cs.FlushFinalBlock(); 
                } 
                return Convert.ToBase64String(ms.ToArray()); 
            } 
            catch
            { 
                throw; 
            } 
        } 
    } 
  
    /// <summary>   
    /// 对DES加密后的字符串进行解密      
    /// </summary>      
    /// <param name="encryptedString">待解密的字符串</param>      
    /// <param name="key">同加密时所采用的key</param> 
    /// <param name="iv">同加密时所采用的iv</param> 
    /// <returns>解密后的字符串</returns>      
    internal static string Decrypt(string src, string key, string iv) 
    { 
        byte[] byteKey = Encoding.Default.GetBytes(key); 
        byte[] byteIv = Encoding.Default.GetBytes(iv); 
        DESCryptoServiceProvider des = new DESCryptoServiceProvider(); 
  
        using (MemoryStream ms = new MemoryStream()) 
        { 
            try