public void TestStringEncryption()
{
// Assamble
string decryptedString = "ABCDEFGHIJKLMNO";
string ecryptedString = "GuGjW6Ae13LGpwxLbCnB9NVkl/RjMUCobImxdPZREmY=";
AesImplementation aes = new AesImplementation();
// Act
string result = aes.Encrypt(decryptedString);
// Assert
Assert.AreEqual(ecryptedString, result);
}
public IAes GetAes(AesImplementation implementation)
{
switch (implementation)
{
case AesImplementation.Asm:
return(new AesAsm());
case AesImplementation.CSharp:
return(new AesCSharp());
default:
return(new AesAsm());
}
}
public static void RunAES(FileInfo input, FileInfo output, String passphrase, bool decrypt, AesImplementation use)
{
if (!input.Exists)
{
Console.ForegroundColor = ConsoleColor.Red;
Console.Error.WriteLine("Input file doesn't exist, exiting.");
Console.ResetColor();
return;
}
string operation = decrypt ? "decryption" : "encryption";
Console.WriteLine($"Performing {operation} using the {use} implementation of the AES-128-ECB algorithm.");
AesFactory aesFactory = new AesFactory();
IAes aes = aesFactory.GetAes(use);
var watch = System.Diagnostics.Stopwatch.StartNew();
if (!decrypt)
{
// Create key using PBKDF2
byte[] salt = new byte[8];
int iterations = 10000;
using (RNGCryptoServiceProvider rngCsp = new RNGCryptoServiceProvider())
{
// Fill the array with a random value.
rngCsp.GetBytes(salt);
}
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(passphrase, salt, iterations, HashAlgorithmName.SHA256);
using (FileStream fs = input.OpenRead())
using (FileStream fsOut = output.OpenWrite())
{
// Mark encrypted file as salted at beginning
string saltedMsg = "Salted__";
byte[] saltedMsgBytes = Encoding.ASCII.GetBytes(saltedMsg);
fsOut.Write(saltedMsgBytes);
// Insert salt into file
fsOut.Write(salt);
byte[] message = new byte[16];
byte[] expandedKey = new byte[176];
aes.KeyExpansion(key.GetBytes(16), expandedKey);
bool ended = false;
while (!ended)
{
int readBytes = fs.Read(message, 0, 16);
if (readBytes == 0) // pad 16 byte block
{
ended = true;
for (int i = 0; i < 16; i++)
{
message[i] = 16;
}
}
else if (readBytes % 16 != 0) // pad missing bytes according to PKCS#7
{
ended = true;
for (int i = 0; i < 16 - readBytes; i++)
{
message[readBytes + i] = (byte)(16 - readBytes);
}
}
aes.Encrypt(message, expandedKey);
fsOut.Write(message, 0, 16);
}
}
}
else
{
using (FileStream fs = input.OpenRead())
using (FileStream fsOut = output.Open(FileMode.Create, FileAccess.ReadWrite))
{
byte[] salt = new byte[8];
fs.Read(salt, 0, 8); // Read first 8 bytes from input file
if (Encoding.ASCII.GetString(salt) == "Salted__") // Check if file is Salted
{
fs.Read(salt, 0, 8); // Read next 8 bytes into salt array
}
int iterations = 10000;
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(passphrase, salt, iterations, HashAlgorithmName.SHA256);
byte[] message = new byte[16];
byte[] expandedKey = new byte[176];
aes.KeyExpansion(key.GetBytes(16), expandedKey);
bool ended = false;
// Store previous decrypted block
byte[] final = new byte[16];
while (!ended)
{
int readBytes = fs.Read(message, 0, 16);
if (readBytes == 0)
{
ended = true;
// Check padding correctness
int n = final[15];
int b = 16;
if (n == 0 || n > 16)
{
Console.ForegroundColor = ConsoleColor.Red;
Console.Error.WriteLine("Bad decrypt (is the supplied passphrase correct?)");
Console.ResetColor();
return;
}
for (int i = 0; i < n; i++)
{
if (final[--b] != n)
{
Console.ForegroundColor = ConsoleColor.Red;
Console.Error.WriteLine("Bad decrypt (is the supplied passphrase correct?)");
Console.ResetColor();
return;
}
}
// Strip padding
fsOut.SetLength(fsOut.Length - n);
fsOut.Close();
}
else
{
aes.Decrypt(message, expandedKey);
for (int i = 0; i < 16; i++)
{
final[i] = message[i];
}
fsOut.Write(message, 0, 16);
}
}
}
}
watch.Stop();
var elapsedMs = watch.ElapsedMilliseconds;
Console.WriteLine($"The selected operation was performed in {elapsedMs} ms.");
}
