image encryption, need help!!

Question

Hello, I am having a hard time encrypting a tiff image.  If anyone can share any insight into this matter, i would appreciate it.

Here is my encrypt method...

private byte[] Encrypt(byte[] bytes)
{
   key = new byte[8];
   iv = new byte[8];
   for (int x = 0; x < 8; x++)
   {
      key[x] = Convert.ToByte(textBox3.Text[x]);
      iv[x] = Convert.ToByte(textBox4.Text[x]);
   }
  
   DESCryptoServiceProvider cryptProvider = new DESCryptoServiceProvider();
   ICryptoTransform transform = cryptProvider.CreateEncryptor(key, iv);
   MemoryStream ms = new MemoryStream();
   CryptoStream cs = new CryptoStream(ms, transform, CryptoStreamMode.Write);
   cs.Write(bytes, 0, bytes.Length);
   cs.FlushFinalBlock();
   ms.Flush();
   return (ms.GetBuffer());
}