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  • 【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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  • 原文地址:https://www.cnblogs.com/DebugLZQ/p/2494927.html
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