.NET C# 加密TXT文件的实现方法

在计算机中，TXT文件是一种常见的文本文件格式，其内容可以比较容易地被其他人读取和修改。如果您需要保护文件的私密性或保密性，您可以考虑使用.NET C#对TXT文件进行加密。本文将为您介绍一种简单的加密方法。

下面是详细的步骤：

1. 准备工作
在开始之前，请确保您已经安装了Visual Studio和.NET框架。

2. 创建加密方法
在C#中，您可以使用Rijndael加密算法对TXT文件进行加密。以下代码演示如何创建一个加密方法：

public static void EncryptFile(string inputFile, string outputFile, string password)
{
    byte[] salt = new byte[8];
    using (var rng = new RNGCryptoServiceProvider())
    {
        rng.GetBytes(salt);
        using (var aes = new RijndaelManaged())
        {
            aes.KeySize = 256;
            aes.BlockSize = 128;
            var key = new Rfc2898DeriveBytes(password, salt, 1000);
            aes.Key = key.GetBytes(aes.KeySize / 8);
            aes.IV = key.GetBytes(aes.BlockSize / 8);
            aes.Mode = CipherMode.CBC;

            using (var fsIn = new FileStream(inputFile, FileMode.Open))
            {
                using (var fsOut = new FileStream(outputFile, FileMode.Create))
                {
                    fsOut.Write(salt, 0, salt.Length);
                    using (var cs = new CryptoStream(fsOut, aes.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        byte[] buffer = new byte[1048576];
                        int read;
                        while ((read = fsIn.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            cs.Write(buffer, 0, read);
                        }
                        cs.FlushFinalBlock();
                        fsOut.Flush();
                    }
                }
            }
        }
    }
}

3. 创建解密方法

同样，您也可以使用Rijndael解密算法对加密的TXT文件进行解密。以下是如何创建一个解密方法的示例代码：

public static void DecryptFile(string inputFile, string outputFile, string password)
{
    byte[] salt = new byte[8];
    using (var fsIn = new FileStream(inputFile, FileMode.Open))
    {
        fsIn.Read(salt, 0, salt.Length);
        using (var aes = new RijndaelManaged())
        {
            aes.KeySize = 256;
            aes.BlockSize = 128;
            var key = new Rfc2898DeriveBytes(password, salt, 1000);
            aes.Key = key.GetBytes(aes.KeySize / 8);
            aes.IV = key.GetBytes(aes.BlockSize / 8);
            aes.Mode = CipherMode.CBC;

            using (var fsOut = new FileStream(outputFile, FileMode.Create))
            {
                using (var cs = new CryptoStream(fsIn, aes.CreateDecryptor(), CryptoStreamMode.Read))
                {
                    byte[] buffer = new byte[1048576];
                    int read;
                    while ((read = cs.Read(buffer, 0, buffer.Length)) > 0)
                    {
                        fsOut.Write(buffer, 0, read);
                    }
                    fsOut.Flush();
                }
            }
        }
    }
}

4. 运行并测试
通过以上的方法，您就可以轻松地对TXT文件进行加密和解密了。您可以使用Visual Studio创建一个简单的C#应用程序，并嵌入上述代码进行测试。

当然也可以不使用密码来进行加密

        public static string EncryptFile(string filepath)
        {
            //加密后的文件名及路径
            string filepathnew = Path.Combine(Path.GetDirectoryName(filepath), Path.GetFileNameWithoutExtension(filepath) + "-加密" + Path.GetExtension(filepath));
            byte[] key = { 24, 55, 102, 24, 98, 26, 67, 29, 84, 19, 37, 118, 104, 85, 121, 27, 93, 86, 24, 55, 102, 24, 98, 26, 67, 29, 9, 2, 49, 69, 73, 92 };
            byte[] IV = { 22, 56, 82, 77, 84, 31, 74, 24, 55, 102, 24, 98, 26, 67, 29, 99 };
            RijndaelManaged myRijndael = new RijndaelManaged();
            using (FileStream fsOut = File.Open(filepathnew, FileMode.Create, FileAccess.Write))
            {
                using (FileStream fsIn = File.Open(filepath, FileMode.Open, FileAccess.Read))
                {
                    //写入加密文本文件
                    using (CryptoStream csDecrypt = new CryptoStream(fsOut, myRijndael.CreateEncryptor(key, IV), CryptoStreamMode.Write))
                    {
                        //读加密文本
                        using (BinaryReader br = new BinaryReader(fsIn))
                        {
                            csDecrypt.Write(br.ReadBytes((int)fsIn.Length), 0, (int)fsIn.Length);
                            csDecrypt.FlushFinalBlock();
                            csDecrypt.Close();
                        }
                    }
                }
            }
            return filepathnew;
        }

        public static string DecipFile(string filepath)
        {
            //加密后的文件名及路径
            string filepathnew = Path.Combine(Path.GetDirectoryName(filepath), Path.GetFileNameWithoutExtension(filepath).Replace("-加密", "") + "-解密" + Path.GetExtension(filepath));
            byte[] key = { 24, 55, 102, 24, 98, 26, 67, 29, 84, 19, 37, 118, 104, 85, 121, 27, 93, 86, 24, 55, 102, 24, 98, 26, 67, 29, 9, 2, 49, 69, 73, 92 };
            byte[] IV = { 22, 56, 82, 77, 84, 31, 74, 24, 55, 102, 24, 98, 26, 67, 29, 99 };
            RijndaelManaged myRijndael = new RijndaelManaged();
            using (FileStream fsOut = File.Open(filepath, FileMode.Open, FileAccess.Read))
            {
                using (CryptoStream csDecrypt = new CryptoStream(fsOut, myRijndael.CreateDecryptor(key, IV), CryptoStreamMode.Read))
                {
                    using (StreamReader sr = new StreamReader(csDecrypt))//把文件读出来
                    {
                        using (StreamWriter sw = new StreamWriter(filepathnew))
                        {
                            //解密后文件写入一个新的文件
                            sw.Write(sr.ReadToEnd());
                            sw.Flush();
                            sw.Close();
                            sr.Close();
                            fsOut.Close();
                        }
                    }
                }
            }
            return filepathnew;
        }