I use this function to decrypt a executable file :
public static string DecryptStringFromBytes_Aes(byte[] cipherText, byte[] Key, byte[] IV) ...
But, this function return a string output I can see the ASCII output of my corresponding decrypted file. But, I need to get a byte[] output.
I have try many thing but I'm stuck: I need a DecryptBytesToBytes function
That function is proprietary - i.e. it's part of your codebase, it's certainly not part of the BCL. So I suggest you find the source code and write a new version that returns a byte array.
As a variant:
static byte[] DecryptBytesToBytes (byte[] cipherText, byte[] Key, byte[] IV)
{
// Check arguments.
if (cipherText == null || cipherText.Length <= 0)
throw new ArgumentNullException("cipherText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("Key");
// Declare the string used to hold
// the decrypted text.
byte[] encrypted = null;
// Create an AesCryptoServiceProvider object
// with the specified key and IV.
using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
{
aesAlg.Key = Key;
aesAlg.IV = IV;
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for decryption.
using (MemoryStream msDecrypt = new MemoryStream(cipherText))
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
{
string encrypted_text = srDecrypt.ReadToEnd();
encrypted = new byte[encrypted_text.Length * sizeof(char)];
System.Buffer.BlockCopy(encrypted_text.ToCharArray(), 0, encrypted, 0, encrypted.Length);
}
}
}
}
return encrypted;
}
The code you posted is for encrypting strings. The following code will encrypt a file and decrypt it using the file path. It will write out the file to the hard disk.
static void EncryptFile(string sInputFilename, string sOutputFilename, byte[] key, byte[] iv)
{
FileStream fsInput = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
FileStream fsEncrypted = new FileStream(sOutputFilename, FileMode.Create, FileAccess.Write);
using (AesCryptoServiceProvider encryptor = new AesCryptoServiceProvider())
{
encryptor.Key = key;
encryptor.IV = iv;
ICryptoTransform transform = encryptor.CreateEncryptor();
using (CryptoStream cryptostream = new CryptoStream(fsEncrypted, transform, CryptoStreamMode.Write))
{
byte[] bytearrayinput = new byte[fsInput.Length];
fsInput.Read(bytearrayinput, 0, bytearrayinput.Length);
cryptostream.Write(bytearrayinput, 0, bytearrayinput.Length);
}
fsInput.Close();
fsEncrypted.Close();
}
}
static void DecryptFile(string sInputFilename, string sOutputFilename, byte[] key, byte[] iv)
{
using (AesCryptoServiceProvider encryptor = new AesCryptoServiceProvider())
{
encryptor.Key = key;
encryptor.IV = iv;
using (FileStream fsread = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read))
{
using (ICryptoTransform transform = encryptor.CreateDecryptor())
{
using (CryptoStream cryptostream = new CryptoStream(fsread, transform, CryptoStreamMode.Read))
{
using (BinaryWriter fsDecrypted = new BinaryWriter(File.Open(sOutputFilename, FileMode.Create)))
{
byte[] buffer = new byte[1024];
var read = cryptostream.Read(buffer, 0, buffer.Length);
while (read > 0)
{
fsDecrypted.Write(buffer, 0, read);
read = cryptostream.Read(buffer, 0, buffer.Length);
}
fsDecrypted.Flush();
cryptostream.Flush();
}
}
}
}
}
}
This works without all the streams:
public static Byte[] Encrypt(Byte[] input, SymmetricAlgorithm crypto)
{
return Transform(crypto.CreateEncryptor(), input, crypto.BlockSize);
}
public static Byte[] Decrypt(Byte[] input, SymmetricAlgorithm crypto)
{
return Transform(crypto.CreateDecryptor(), input, crypto.BlockSize);
}
private static Byte[] Transform(ICryptoTransform cryptoTransform, Byte[] input, Int32 blockSize)
{
if (input.Length > blockSize)
{
Byte[] ret1 = new Byte[( ( input.Length - 1 ) / blockSize ) * blockSize];
Int32 inputPos = 0;
Int32 ret1Length = 0;
for (inputPos = 0; inputPos < input.Length - blockSize; inputPos += blockSize)
{
ret1Length += cryptoTransform.TransformBlock(input, inputPos, blockSize, ret1, ret1Length);
}
Byte[] ret2 = cryptoTransform.TransformFinalBlock(input, inputPos, input.Length - inputPos);
Byte[] ret = new Byte[ret1Length + ret2.Length];
Array.Copy(ret1, 0, ret, 0, ret1Length);
Array.Copy(ret2, 0, ret, ret1Length, ret2.Length);
return ret;
}
else
{
return cryptoTransform.TransformFinalBlock(input, 0, input.Length);
}
}
