c# 图片加密解密的实例代码

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())
{
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

}
}