C#

Process curProcess = Process.GetCurrentProcess();
curProcess.PriorityClass = ProcessPriorityClass.High; // or .RealTime;

using System.Threading;

class Class1 {
  static void Encrypt(string inputFile, string outputFile) {
    FileStream fsin = new FileStream(inputFile, FileMode.Open, FileAccess.Read);

    FileStream fsout = new FileStream(outputFile, FileMode.Create, FileAccess.Write);

    byte[] key = new byte[] {22,184,62,104,66,100,202,17,91,254,197,181,224,62,36,138,128,227,146,111,134,83,241,125};
    byte[] iv = new byte[] {216,237,102,42,142,11,133,104};

    TripleDESCryptoServiceProvider tripleDes = new TripleDESCryptoServiceProvider();
    ICryptoTransform t = tripleDes.CreateEncryptor(key, iv);

    CryptoStream cs = new CryptoStream(fsout, t, CryptoStreamMode.Write);

    int len = (int) fsin.Length;
    byte[] buffer = new byte[len];
    len = fsin.Read(buffer, 0, len);
    cs.Write(buffer, 0, len);

    cs.Close();
    fsout.Close();
    fsin.Close();
  }

  static void Decrypt(string inputFile, string outputFile) {
    FileStream fsin = new FileStream(inputFile, FileMode.Open, FileAccess.Read);

    FileStream fsout = new FileStream(outputFile, FileMode.Create, FileAccess.Write);

    byte[] key = new byte[] {22,184,62,104,66,100,202,17,91,254,197,181,224,62,36,138,128,227,146,111,134,83,241,125};
    byte[] iv = new byte[] {216,237,102,42,142,11,133,104};

    TripleDESCryptoServiceProvider tripleDes = new TripleDESCryptoServiceProvider();
    ICryptoTransform t = tripleDes.CreateDecryptor(key, iv);

    CryptoStream cs = new CryptoStream(fsout, t, CryptoStreamMode.Write);

    int len = (int) fsin.Length;
    byte[] buffer = new byte[len];
    len = fsin.Read(buffer, 0, len);
    cs.Write(buffer, 0, len);

    cs.Close();
    fsout.Close();
    fsin.Close();
  }

  static void Main(string[] args) {

    Console.WriteLine("Starting encryption...");
    Encrypt(@"c:\test.txt", @"c:\test.enc");
    Console.WriteLine("...done");

    Console.WriteLine("Starting decryption...");
    Decrypt(@"c:\test.enc", @"c:\test.dec");
    Console.WriteLine("...done");

    Console.ReadLine();
  }
}

[DllImport("user32.dll", CharSet=CharSet.Auto)]
private extern static int SendMessage(IntPtr hwnd, int msg, int wParam, ref COPYDATASTRUCT lParam);
 
[StructLayout(LayoutKind.Sequential)]
struct COPYDATASTRUCT {  // cds 
    int dwData; 
    int cbData; 
    IntPtr lpData; 
}
 
//------Managed Way--------
 
//assume that the variable "data" holds the data
 
COPYDATASTRUCT cds=new COPYDATASTRUCT;
 
cds.cbData=Marshall.SizeOf(data);
IntPtr mem=Marshall.AllocHGlobal(cds.cbData);
cds.lpData=Marshall.StructureToPtr(data,mem,true);
cds.lpData=mem;
//now do the SendMessage call, then do cleanup of resources
 
//-----UnManaged Way------
 
[DllImport("user32.dll", CharSet=CharSet.Auto)]
private extern static int SendMessage(IntPtr hwnd, int msg, int wParam, void* lParam);
 
COPYDATASTRUCT cds=new COPYDATASTRUCT;
SendMessage(handle,WM_COPYDATA,wParam,(void*)&cds);
 

cds.lpData=Marshall.StructureToPtr(data,mem,true);

Marshall.StructureToPtr(data,mem,true);