C#加密解密文件小工具

前面一篇博文中，分享了一个文件夹加密小工具，该工具是操作文件夹名称的方法实现文件夹的一般加密，文件夹中的文件（视频、图片等）都原封不动的保存在那里。

　　DebugLZQ在网上搜索相关文件加密的程序，发现给出的基本都是针对“字符创”、“文本”的加密与解密。对视频文件、图片等一般文件的加密解密程序少之又少，故写下此文，实现一个对一般文件进行加密的小工具。

　　程序的主要功能是：用户通过文件选择框选择要加密的文件-》输入密码进行加密；选择加密后的文件，输入密码进行解密。

　　程序的主界面如下：

　　三个按钮的Click事件处理程序如下：

        private void btnSelectFile_Click(object sender, EventArgs e)        {            if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)            {                txtFileName.Text = openFileDialog1.FileName ;            }        }        private void btnEncryptFile_Click(object sender, EventArgs e)        {            string inFile=txtFileName.Text;            string outFile = inFile + ".dat";            string password=txtPassword.Text ;            DESFile.DESFileClass.EncryptFile(inFile, outFile, password);//加密文件            //删除加密前的文件            File.Delete(inFile);            txtFileName.Text = string.Empty;            MessageBox.Show("加密成功");        }        private void btnDecryptFile_Click(object sender, EventArgs e)        {            string inFile = txtFileName.Text;            string outFile = inFile.Substring(0,inFile.Length - 4);            string password = txtPassword.Text;            DESFile.DESFileClass.DecryptFile (inFile, outFile, password);//解密文件            //删除解密前的文件            File.Delete(inFile);            txtFileName.Text = string.Empty;            MessageBox.Show("解密成功");        }

　　加密解密的Help文件源码如下：

using System;using System.Collections.Generic;using System.Text;using System.Security.Cryptography;using System.IO;namespace DESFile{    /// <summary>    /// 异常处理类    /// </summary>    public class CryptoHelpException : ApplicationException    {        public CryptoHelpException(string msg) : base(msg) { }    }    /// <summary>    /// CryptHelp    /// </summary>    public class DESFileClass    {        private const ulong FC_TAG = 0xFC010203040506CF;        private const int BUFFER_SIZE = 128 * 1024;        /// <summary>        /// 检验两个Byte数组是否相同        /// </summary>        /// <param name="b1">Byte数组</param>        /// <param name="b2">Byte数组</param>        /// <returns>true－相等</returns>        private static bool CheckByteArrays(byte[] b1, byte[] b2)        {            if (b1.Length == b2.Length)            {                for (int i = 0; i < b1.Length; ++i)                {                    if (b1[i] != b2[i])                        return false;                }                return true;            }            return false;        }        /// <summary>        /// 创建DebugLZQ ,http://www.cnblogs.com/DebugLZQ        /// </summary>        /// <param name="password">密码</param>        /// <param name="salt"></param>        /// <returns>加密对象</returns>        private static SymmetricAlgorithm CreateRijndael(string password, byte[] salt)        {            PasswordDeriveBytes pdb = new PasswordDeriveBytes(password, salt, "SHA256", 1000);            SymmetricAlgorithm sma = Rijndael.Create();            sma.KeySize = 256;            sma.Key = pdb.GetBytes(32);            sma.Padding = PaddingMode.PKCS7;            return sma;        }        /// <summary>        /// 加密文件随机数生成        /// </summary>        private static RandomNumberGenerator rand = new RNGCryptoServiceProvider();        /// <summary>        /// 生成指定长度的随机Byte数组        /// </summary>        /// <param name="count">Byte数组长度</param>        /// <returns>随机Byte数组</returns>        private static byte[] GenerateRandomBytes(int count)        {            byte[] bytes = new byte[count];            rand.GetBytes(bytes);            return bytes;        }        /// <summary>        /// 加密文件        /// </summary>        /// <param name="inFile">待加密文件</param>        /// <param name="outFile">加密后输入文件</param>        /// <param name="password">加密密码</param>        public static void EncryptFile(string inFile, string outFile, string password)        {            using (FileStream fin = File.OpenRead(inFile),                fout = File.OpenWrite(outFile))            {                long lSize = fin.Length; // 输入文件长度                int size = (int)lSize;                byte[] bytes = new byte[BUFFER_SIZE]; // 缓存                int read = -1; // 输入文件读取数量                int value = 0;                // 获取IV和salt                byte[] IV = GenerateRandomBytes(16);                byte[] salt = GenerateRandomBytes(16);                // 创建加密对象                SymmetricAlgorithm sma = DESFileClass.CreateRijndael(password, salt);                sma.IV = IV;                // 在输出文件开始部分写入IV和salt                fout.Write(IV, 0, IV.Length);                fout.Write(salt, 0, salt.Length);                // 创建散列加密                HashAlgorithm hasher = SHA256.Create();                using (CryptoStream cout = new CryptoStream(fout, sma.CreateEncryptor(), CryptoStreamMode.Write),                    chash = new CryptoStream(Stream.Null, hasher, CryptoStreamMode.Write))                {                    BinaryWriter bw = new BinaryWriter(cout);                    bw.Write(lSize);                    bw.Write(FC_TAG);                    // 读写字节块到加密流缓冲区                    while ((read = fin.Read(bytes, 0, bytes.Length)) != 0)                    {                        cout.Write(bytes, 0, read);                        chash.Write(bytes, 0, read);                        value += read;                    }                    // 关闭加密流                    chash.Flush();                    chash.Close();                    // 读取散列                    byte[] hash = hasher.Hash;                    // 输入文件写入散列                    cout.Write(hash, 0, hash.Length);                    // 关闭文件流                    cout.Flush();                    cout.Close();                }            }        }        /// <summary>        /// 解密文件        /// </summary>        /// <param name="inFile">待解密文件</param>        /// <param name="outFile">解密后输出文件</param>        /// <param name="password">解密密码</param>        public static void DecryptFile(string inFile, string outFile, string password)        {            // 创建打开文件流            using (FileStream fin = File.OpenRead(inFile),                fout = File.OpenWrite(outFile))            {                int size = (int)fin.Length;                byte[] bytes = new byte[BUFFER_SIZE];                int read = -1;                int value = 0;                int outValue = 0;                byte[] IV = new byte[16];                fin.Read(IV, 0, 16);                byte[] salt = new byte[16];                fin.Read(salt, 0, 16);                SymmetricAlgorithm sma = DESFileClass.CreateRijndael(password, salt);                sma.IV = IV;                value = 32;                long lSize = -1;                // 创建散列对象, 校验文件                HashAlgorithm hasher = SHA256.Create();                using (CryptoStream cin = new CryptoStream(fin, sma.CreateDecryptor(), CryptoStreamMode.Read),                    chash = new CryptoStream(Stream.Null, hasher, CryptoStreamMode.Write))                {                    // 读取文件长度                    BinaryReader br = new BinaryReader(cin);                    lSize = br.ReadInt64();                    ulong tag = br.ReadUInt64();                    if (FC_TAG != tag)                        throw new CryptoHelpException("文件被破坏");                    long numReads = lSize / BUFFER_SIZE;                    long slack = (long)lSize % BUFFER_SIZE;                    for (int i = 0; i < numReads; ++i)                    {                        read = cin.Read(bytes, 0, bytes.Length);                        fout.Write(bytes, 0, read);                        chash.Write(bytes, 0, read);                        value += read;                        outValue += read;                    }                    if (slack > 0)                    {                        read = cin.Read(bytes, 0, (int)slack);                        fout.Write(bytes, 0, read);                        chash.Write(bytes, 0, read);                        value += read;                        outValue += read;                    }                    chash.Flush();                    chash.Close();                    fout.Flush();                    fout.Close();                    byte[] curHash = hasher.Hash;                    // 获取比较和旧的散列对象                    byte[] oldHash = new byte[hasher.HashSize / 8];                    read = cin.Read(oldHash, 0, oldHash.Length);                    if ((oldHash.Length != read) || (!CheckByteArrays(oldHash, curHash)))                        throw new CryptoHelpException("文件被破坏");                }                if (outValue != lSize)                    throw new CryptoHelpException("文件大小不匹配");            }        }    }}