【C#文件锁】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); } } }}

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~

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