Sk9*_*k93 7 c# encryption encryption-symmetric rijndaelmanaged
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形式加密和解密文件,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,但在解密过程中,"cryptoStream.Close()"方法抛出以下异常:
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 ()
还显示出未加密的文件大小不匹配预期的文件大小(范围从大约8个字节,以大约60)
我通过改变RijndaelManaged对象创建行来"修复"异常以包含填充类型,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,我现在我的加密/解密的舒适区之外,它可能是一个新手的错误 - 但我不能发现它!
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