Rijndael的文件加密问题Rijndael的文件加密问题
我要加密使用Rijndael算法大型文件,但我走出内存异常错误的。任何想法? 这里是我的代码
public void Rijndael_EncryptFile(string password, string filepath, int opt)
{
try
{
byte[] keyBytes;
keyBytes = Encoding.Unicode.GetBytes(password);
Rfc2898DeriveBytes derivedKey = new Rfc2898DeriveBytes(password, keyBytes);
RijndaelManaged rijndaelCSP = new RijndaelManaged();
rijndaelCSP.BlockSize = opt; //128 256
rijndaelCSP.KeySize = opt; //128 256
rijndaelCSP.Key = derivedKey.GetBytes(rijndaelCSP.KeySize/8);
rijndaelCSP.IV = derivedKey.GetBytes(rijndaelCSP.BlockSize/8);
rijndaelCSP.Mode = CipherMode.CFB;
rijndaelCSP.Padding = PaddingMode.Zeros;
ICryptoTransform encryptor = rijndaelCSP.CreateEncryptor();
FileStream inputFileStream = new FileStream(filepath, FileMode.Open, FileAccess.Read);
byte[] inputFileData = new byte[(int)inputFileStream.Length];
inputFileStream.Read(inputFileData, 0, (int)inputFileStream.Length);
FileStream outputFileStream = new FileStream(filepath + ".enc", FileMode.Create, FileAccess.Write);
CryptoStream encryptStream = new CryptoStream(outputFileStream, encryptor, CryptoStreamMode.Write);
encryptStream.Write(inputFileData, 0, (int)inputFileStream.Length);
encryptStream.FlushFinalBlock();
rijndaelCSP.Clear();
encryptStream.Close();
inputFileStream.Close();
outputFileStream.Close();
}
}
对于CFB模式,IV必须*唯一*。不要使用静态IV,因为这会使密码具有确定性,因此在语义上不安全。观察密文的攻击者可以确定何时之前发送了相同的消息前缀。对于像CFB这样的流式传输模式,甚至更糟糕的是,即使消息不同时,攻击者甚至能够推断出消息IV是否被重用。 IV不是秘密的,所以你可以把它和密文一起发送。通常,它只是在密文前面加上,然后在解密之前切掉。 –