对大文件使用Rijndael加密
我需要安全地加密/解密n长度的文件，理想情况下使用Rijndael，但绝对是256位加密。
我以前玩过加密，并且非常高兴地加密/解密字符串和字节数组。 但是，因为我不知道文件的大小（并且所讨论的文件可能非常大（~2.5gb）非常可行，我不能只将它们加载到字节数组中并对它们进行加密/解密像我以前一样受限制。
因此，经过对Google的一些阅读后，我知道答案是以块的forms加密和解密文件，因此我生成了以下代码：
private static void Enc(string decryptedFileName, string encryptedFileName) { FileStream fsOutput = File.OpenWrite(encryptedFileName); FileStream fsInput = File.OpenRead(decryptedFileName); byte[] IVBytes = Encoding.ASCII.GetBytes("1234567890123456"); fsOutput.Write(BitConverter.GetBytes(fsInput.Length), 0, 8); fsOutput.Write(IVBytes, 0, 16); RijndaelManaged symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC}; ICryptoTransform encryptor = symmetricKey.CreateEncryptor(passwordDB.GetBytes(256 / 8), IVBytes); CryptoStream cryptoStream = new CryptoStream(fsOutput, encryptor, CryptoStreamMode.Write); for (long i = 0; i < fsInput.Length; i += chunkSize) { byte[] chunkData = new byte[chunkSize]; fsInput.Read(chunkData, 0, chunkSize); cryptoStream.Write(chunkData, 0, chunkData.Length); } cryptoStream.Close(); fsInput.Close(); fsInput.Dispose(); cryptoStream.Dispose(); } private static void Dec(string encryptedFileName, string decryptedFileName) { FileStream fsInput = File.OpenRead(encryptedFileName); FileStream fsOutput = File.OpenWrite(decryptedFileName); byte[] buffer = new byte[8]; fsInput.Read(buffer, 0, 8); long fileLength = BitConverter.ToInt64(buffer, 0); byte[] IVBytes = new byte[16]; fsInput.Read(IVBytes, 0, 16); RijndaelManaged symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC }; ICryptoTransform decryptor = symmetricKey.CreateDecryptor(passwordDB.GetBytes(256 / 8), IVBytes); CryptoStream cryptoStream = new CryptoStream(fsOutput,decryptor,CryptoStreamMode.Write); for (long i = 0; i < fsInput.Length; i += chunkSize) { byte[] chunkData = new byte[chunkSize]; fsInput.Read(chunkData, 0, chunkSize); cryptoStream.Write(chunkData, 0, chunkData.Length); } cryptoStream.Close(); cryptoStream.Dispose(); fsInput.Close(); fsInput.Dispose(); } 这对我来说“看起来很好”，但遗憾的是看起来似乎是在欺骗！
加密工作没有错误，但在解密期间，“cryptoStream.Close（）”方法抛出以下exception：
System.Security.Cryptography.CryptographicException未处理Message =“填充无效，无法删除。”
Source =“mscorlib”StackTrace：在System.Security.Cryptography的System.Security.Cryptography.RijndaelManagedTransform.DecryptData（Byte [] inputBuffer，Int32 inputOffset，Int32 inputCount，Byte []＆outputBuffer，Int32 outputOffset，PaddingMode paddingMode，Boolean fLast） .RijndaelManagedTransform.TransformFinalBlock（Byte [] inputBuffer，Int32 inputOffset，Int32 inputCount）在System.Security.Cryptography.CryptoStream.FlushFinalBlock（）处于System.Security.Cryptography.CryptoStream.Dispose（布局处理）System.IO.Stream.Close （）
看来未加密的文件大小与预期的文件大小不匹配（范围从大约8个字节到大约60个）
我通过改变RijndaelManaged对象创建行来“修复”exception以包含填充类型，如下所示：
RijndaelManaged symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC,Padding=PaddingMode.None };
但文件大小仍然不匹配，可以预见，新近未加密的文件是胡扯！
我承认我现在已经超出了加密/解密的舒适区域，这可能是一个新手的错误 – 但我无法发现它！
任何有关解决此问题的帮助将不胜感激！
问题是我正在使用：
passwordDB.GetBytes(256 / 8)
在加密和解密方法中的RijndaelManaged对象的构造函数中，我没有在尝试解密之前重新初始化passwordDB对象。
解决方案是简单地在Enc和Dec方法的第一行中包含passwordDB对象的构造，如下所示：
private static void Enc(string decryptedFileName, string encryptedFileName) { PasswordDeriveBytes passwordDB = new PasswordDeriveBytes("ThisIsMyPassword", Encoding.ASCII.GetBytes("thisIsMysalt!"), "MD5", 2); byte[] passwordBytes = passwordDB.GetBytes(128 / 8); using (FileStream fsOutput = File.OpenWrite(encryptedFileName)) { using(FileStream fsInput = File.OpenRead(decryptedFileName)) { byte[] IVBytes = Encoding.ASCII.GetBytes("1234567890123456"); fsOutput.Write(BitConverter.GetBytes(fsInput.Length), 0, 8); fsOutput.Write(IVBytes, 0, 16); RijndaelManaged symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC,Padding=PaddingMode.ANSIX923}; ICryptoTransform encryptor = symmetricKey.CreateEncryptor(passwordBytes, IVBytes); using (CryptoStream cryptoStream = new CryptoStream(fsOutput, encryptor, CryptoStreamMode.Write)) { for (long i = 0; i < fsInput.Length; i += chunkSize) { byte[] chunkData = new byte[chunkSize]; int bytesRead = 0; while ((bytesRead = fsInput.Read(chunkData, 0, chunkSize)) > 0) { if (bytesRead != 16) { for (int x = bytesRead - 1; x < chunkSize; x++) { chunkData[x] = 0; } } cryptoStream.Write(chunkData, 0, chunkSize); } } cryptoStream.FlushFinalBlock(); } } } } private static void Dec(string encryptedFileName, string decryptedFileName) { PasswordDeriveBytes passwordDB = new PasswordDeriveBytes("ThisIsMyPassword", Encoding.ASCII.GetBytes("thisIsMysalt!"), "MD5", 2); byte[] passwordBytes = passwordDB.GetBytes(128 / 8); using (FileStream fsInput = File.OpenRead(encryptedFileName)) { using (FileStream fsOutput = File.OpenWrite(decryptedFileName)) { byte[] buffer = new byte[8]; fsInput.Read(buffer, 0, 8); long fileLength = BitConverter.ToInt64(buffer, 0); byte[] IVBytes = new byte[16]; fsInput.Read(IVBytes, 0, 16); RijndaelManaged symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC,Padding=PaddingMode.ANSIX923}; ICryptoTransform decryptor = symmetricKey.CreateDecryptor(passwordBytes, IVBytes); using (CryptoStream cryptoStream = new CryptoStream(fsOutput, decryptor, CryptoStreamMode.Write)) { for (long i = 0; i < fsInput.Length; i += chunkSize) { byte[] chunkData = new byte[chunkSize]; int bytesRead = 0; while ((bytesRead = fsInput.Read(chunkData, 0, chunkSize)) > 0) { cryptoStream.Write(chunkData, 0, bytesRead); } } } } } }
知道它必须是一个男生错误：P
Stream.Read方法返回实际从流中读取的字节数。
您应该将此返回值用作下一行Write方法中的最后一个参数。
我的代码看起来像这样：
byte[] chunkData = new byte[chunkSize]; var bytesRead = 0; while ((bytesRead = fsInput.Read(chunkData, 0, chunkSize)) > 0) { cryptoStream.Write(chunkData, 0, bytesRead); }
有一个CryptoStream类来加密/解密Streams