C# 图片的加密和解密

[熊思宇]

using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
using System.IO;
 
namespace Utils
{
    /// <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
 
    }
}

end