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：


	复制代码 代码如下:

	

	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：


	复制代码 代码如下:

	

	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");

	}

	}

	}

	}


加密/解密结果：

以加密D盘下的1.avi为例，加密后的文件为1.avi.dat，即使重命名回1.avi文件依然无法打开（文件被加密）。


	

	输入密码进行解密后，文件恢复解密，可以顺利打开~