private static void aesEncryptFile(CipherMode mode, byte[] keyBytes, byte[] ivBytes, string inputFile, string outputFile)
{
//Setting Up the AES object
Aes aes = Aes.Create();
aes.Mode = mode;
aes.Key = keyBytes;
//For ECB it will ignore the IV anyway so we dont have to worry about checking mode
if (ivBytes != null)
{
aes.IV = ivBytes;
}
else
{
// In the case where the user has not provided the IV
// It will print the IV to the console. We would not usally do
// this. But this allows me to check my output.
printIV(aes.IV);
}
// The Assignment doesn't seem require us to create code that will decrpyt the file as well.
// However, if you wanted to decrypt as well, it would be the same code as this method except
// here you would call aes.CreateDecryptor().
ICryptoTransform cryptoTransform = aes.CreateEncryptor();
// Here we open the input file
using (FileStream outputFileStream = new FileStream(outputFile, FileMode.Create))
{
using (CryptoStream cryptoStream = new CryptoStream(outputFileStream, cryptoTransform, CryptoStreamMode.Write))
{
// We are reading in blocks in a time just to make it a bit faster
var totalBytesRead = 0;
var offset = 0;
// This is how many bits per block we read in a time. However, it
// However, this has nothing do with AES block size. We could choose
// any block size. But we might as well use the AES block size and
// hopefully save some padding.
int inputBlockSize = 128;
byte[] inputData = new byte[inputBlockSize];
using (FileStream inputFileStream = new FileStream(inputFile, FileMode.Open))
{
var bytesRead = 0;
do
{
bytesRead = inputFileStream.Read(inputData, 0, inputBlockSize);
offset += bytesRead;
// The Crypto Stream will use the transformer we declared above
// to actually carry out the transformation.
cryptoStream.Write(inputData, 0, bytesRead);
totalBytesRead += bytesRead;
}while (bytesRead > 0);
inputFileStream.Close();
}
cryptoStream.FlushFinalBlock();
cryptoStream.Close();
}
outputFileStream.Close();
}
}
private void encryptButton_Click(object sender, RoutedEventArgs e)
{
string str = putTextBox.Text;
UnicodeEncoding asen = new UnicodeEncoding();
ASCIIEncoding ascii = new ASCIIEncoding();
// Key
byte[] key = new byte[16];
int padNum = 0;
string keystr;
if (16 < keyBox.GetLineLength(0))
{
MessageBox.Show("Key too long...Only use 16 bytes");
return;
}
else if (16 > keyBox.GetLineLength(0))
{
padNum = 16 - keyBox.GetLineLength(0);
keystr = keyBox.Text;
for (int i = 0; i < padNum; i++)
{
keystr += "x";
}
key = ascii.GetBytes(keystr);
}
else
{
key = ascii.GetBytes(keyBox.Text);
}
// Encrypt the string to an array of bytes.
byte[] encrypted;
byte[] IV;
// Time analysis of encryption
using (Aes aesAlg = Aes.Create())
{
aesAlg.Key = key;
aesAlg.GenerateIV();
IV = aesAlg.IV;
aesAlg.Mode = CipherMode.ECB;
var encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
using (var msEncrypt = new MemoryStream())
{
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (var swEncrypt = new StreamWriter(csEncrypt))
{
//Write all data to the stream.
swEncrypt.Write(str);
}
encrypted = msEncrypt.ToArray();
}
}
}
var combinedIvCt = new byte[IV.Length + encrypted.Length];
Array.Copy(IV, 0, combinedIvCt, 0, IV.Length);
Array.Copy(encrypted, 0, combinedIvCt, IV.Length, encrypted.Length);
string output = System.Convert.ToBase64String(combinedIvCt);
// combinedIvCt is now the encrypted message
putTextBox.Text = output;
}