逐行加密/解密文件？

我对加密还很陌生，我正在尝试让逐行加密器工作；我需要能够在应用程序运行期间将加密行附加到文件中，而不仅仅是一大堆加密所有内容并保存。不过我玩得很开心。这是我的加密器，在我自己多次尝试失败后被无耻地窃取：

class Encryption
    {
        private static readonly byte[] SALT = new byte[] { 0x26, 0xdc, 0xff, 0x00, 0xad, 0xed, 0x7a, 0xee, 0xc5, 0xfe, 0x07, 0xaf, 0x4d, 0x08, 0x22, 0x3c };

        public static byte[] Encrypt(byte[] plain, string password)
        {
            MemoryStream memoryStream;
            CryptoStream cryptoStream;
            Rijndael rijndael = Rijndael.Create();
            Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(password, SALT);
            rijndael.Key = pdb.GetBytes(32);
            rijndael.IV = pdb.GetBytes(16);
            memoryStream = new MemoryStream();
            cryptoStream = new CryptoStream(memoryStream, rijndael.CreateEncryptor(), CryptoStreamMode.Write);
            cryptoStream.Write(plain, 0, plain.Length);
            cryptoStream.FlushFinalBlock();
            cryptoStream.Close();
            return memoryStream.ToArray();
        }

        public static byte[] Decrypt(byte[] cipher, string password)
        {
            MemoryStream memoryStream;
            CryptoStream cryptoStream;
            Rijndael rijndael = Rijndael.Create();
            Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(password, SALT);
            rijndael.Key = pdb.GetBytes(32);
            rijndael.IV = pdb.GetBytes(16);
            memoryStream = new MemoryStream();
            cryptoStream = new CryptoStream(memoryStream, rijndael.CreateDecryptor(), CryptoStreamMode.Write);
            cryptoStream.Write(cipher, 0, cipher.Length);
            cryptoStream.FlushFinalBlock();
            cryptoStream.Close();
            return memoryStream.ToArray();
        }
    }

这是一个虚拟函数，展示了我如何尝试它：

       private void EncryptFile(string filepath, string outputPath, string password)
        {
            FileInfo fileInfo = new FileInfo(filepath);
            string filename = fileInfo.Name;

            string fullpath = outputPath + "\\" + filename;

            BinaryWriter writer = new BinaryWriter(File.OpenWrite(fullpath), Encoding.ASCII);

            /// Two methods that I've attempted here:
            /// 1.  The desired method: encrypt line by line - I assumed I'd be able to generate
            ///     multiple blocks of data and decrypt them later.  This isn't working

            //string[] lines = File.ReadAllLines(filepath);

            /// 2.  Just read the whole thing and encrypt and write it in one swoop.

            string line = File.ReadAllText(filepath);

            //foreach(string line in lines)
            {
                byte[] bytes = Encoding.ASCII.GetBytes(line);
                byte[] encoded = Encryption.Encrypt(bytes, password);

                writer.Write(encoded);
                writer.Flush();
            }

            writer.Close();
        }



        private void DecryptFile(string filepath, string outputPath, string password)
        {
            FileInfo fileInfo = new FileInfo(filepath);
            string filename = fileInfo.Name;
            string fullpath = outputPath + "\\" + filename;

            StreamWriter writer = new StreamWriter(fullpath, false, Encoding.UTF8);

            byte[] bytes = File.ReadAllBytes(filepath);

            ///  Here is the method that's working at the moment for decrypting; just
            ///  grab all the data and decrypt it on one swoop.

            byte[] decrypted = Encryption.Decrypt(bytes, password);

            string s = Encoding.ASCII.GetString(decrypted);

            writer.Write(s);
            writer.Flush();


            ///  I've tried a number of things here to decrypt line by line,
            ///  none of which work.  This crashes with an issue about the padding
            ///  being invalid.  

            /*
            int index = 0;
            int count = 32;

            while (index   

我不完全确定我应该做什么了。我一直在网上闲逛并阅读示例，但它们似乎都是如何加密整个文件或只是加密一段数据并且除了立即再次解密之外不对其执行任何操作。我应该如何处理逐行写作？

我不会为您编写此程序，而是为您提供一个可以实施的方案。

如果您有每行加密，我想您也希望能够解密每行。请注意，“线”对于计算机来说是一个相当不方便的术语。它只是一堆以某种行终止符结尾的字符。字符本身是使用特定的编码字符编码 /questions/tagged/character-encoding.

此外，我将做出以下假设：

• 加密文本应以行形式呈现，这意味着字节需要从二进制转换为字符（使用encoding /questions/tagged/encoding);
• 您希望使用单一密钥，同时保持安全；
• 您不需要完整性保护或密文验证，只需要机密性。

现在的想法很简单：

1. 使用基于密码的密钥派生函数创建单个密钥；
2. 打开文本文件进行阅读（使用正确的字符编码 /questions/tagged/character-encoding);
3. 读取一行并再次将该行转换为字节（例如使用 UTF-8）；
4. 创建一个输出流，该输出流在下面创建一个字节数组；
5. 创建一个随机 IV 并将其写入字节数组（IV 始终是单个块大小）；
6. 创建一个加密流并将其连接到相同的输出流；
7. 加密编码行；
8. 对加密字节进行 Base 64 编码，并确保其位于一行；
9. 将编码的加密行写入新的文本文件。

要执行相反的操作，请颠倒该过程，尽管 IV 应从 Base 64 解码后的字节中检索，并且密钥当然应使用与加密期间使用的相同方法来计算。