using System;  using System.Collections.Generic;  using System.Text;  using System.Security.Cryptography;  using System.IO;  namespace Net.Template.Common  {  /// <summary>  /// 对图片的加密和解密  /// </summary>  public class DEncrypt4ImageHelper  {  public DEncrypt4ImageHelper() { }  #region 加密方法 图片加密  /// <summary>  /// 图片加密  /// </summary>  /// <param name="filePath">源文件</param>  /// <param name="savePath">保存为文件名称</param>  /// <param name="keyStr">密钥</param>  public static void EncryptFile(string filePath, string savePath, string keyStr)  {  //通过des加密  DESCryptoServiceProvider des = new DESCryptoServiceProvider();  //通过流打开文件  FileStream fs = File.OpenRead(filePath);  //获取文件二进制字符  byte[] inputByteArray = new byte[fs.Length];  //读流文件  fs.Read(inputByteArray, 0, (int)fs.Length);  //关闭流  fs.Close();  //获得加密字符串二进制字符  byte[] keyByteArray = Encoding.Default.GetBytes(keyStr);  //计算指定字节组指定区域哈希值  SHA1 ha = new SHA1Managed();  byte[] hb = ha.ComputeHash(keyByteArray);  //加密密钥数组  byte[] sKey = new byte[8];  //加密变量  byte[] sIV = new byte[8];  for (int i = 0; i < 8; i++)  sKey[i] = hb[i];  for (int i = 8; i < 16; i++)  sIV[i - 8] = hb[i];  //获取加密密钥  des.Key = sKey;  //设置加密初始化向量  des.IV = sIV;  MemoryStream ms = new MemoryStream();  CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);  cs.Write(inputByteArray, 0, inputByteArray.Length);  cs.FlushFinalBlock();  fs = File.OpenWrite(savePath);  foreach (byte b in ms.ToArray())  { www.jbxue.com  fs.WriteByte(b);  }  fs.Close();  cs.Close();  ms.Close();  }  #endregion  #region 解密方法 图片解密  /// <summary>  /// 图片解密  /// </summary>  /// <param name="filePath">源文件</param>  /// <param name="savePath">保存文件</param>  /// <param name="keyStr">密钥</param>  public static void DecryptFile(string filePath, string savePath, string keyStr)  {  //通过des解密  DESCryptoServiceProvider des = new DESCryptoServiceProvider();  //通过流读取文件  FileStream fs = File.OpenRead(filePath);  //获取文件二进制字符  byte[] inputByteArray = new byte[fs.Length];  //读取流文件  fs.Read(inputByteArray, 0, (int)fs.Length);  //关闭流  fs.Close();  //密钥数组  byte[] keyByteArray = Encoding.Default.GetBytes(keyStr);  //定义哈希变量  SHA1 ha = new SHA1Managed();  //计算指定字节组指定区域哈希值  byte[] hb = ha.ComputeHash(keyByteArray);  //加密密钥数组  byte[] sKey = new byte[8];  //加密变量  byte[] sIV = new byte[8];  for (int i = 0; i < 8; i++)  sKey[i] = hb[i];  for (int i = 8; i < 16; i++)  sIV[i - 8] = hb[i];  //获取加密密钥  des.Key = sKey;  //加密变量  des.IV = sIV;  MemoryStream ms = new MemoryStream();  CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);  cs.Write(inputByteArray, 0, inputByteArray.Length);  cs.FlushFinalBlock();  fs = File.OpenWrite(savePath);  foreach (byte b in ms.ToArray())  {  fs.WriteByte(b);  }  fs.Close();  cs.Close();  ms.Close();  }  #endregion  }  }