How to Play decrypted file - asp.net

Question

For video's to be copy protected , I thought of
Step-1) encrypting video files with key.
step-2)Decrypting a file OR decrypt in memory stream.
Step-3) Play decrypted file OR Play from Memory stream.
I have succesfully encrypted and decrypted a video file with key. But don't know how to play decrypted file(.dnc file).
Can somebody will please help me to play video file from decrypted (File or Memory Stream).
Code for Decryption
private void Decryption(string filePath)
{
try
{
DateTime current = DateTime.Now;
string encName = filePath + "data" + ".enc";
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
#region Seperate key and data
byte[] alldata = File.ReadAllBytes(filePath);
byte[] getencryptedkey = new byte[128];
byte[] data = new byte[alldata.Length - 128];
for (int i = 0; i < alldata.Length - 128; i++)
{ data[i] = alldata[i]; }
for (int i = alldata.Length - 128, j = 0; i < alldata.Length; i++, j++)
{ getencryptedkey[j] = alldata[i]; }
using (BinaryWriter bw = new BinaryWriter(File.Create(encName)))
{
bw.Write(data);
bw.Close();
}
#endregion
#region key decryption
StreamReader reader = new StreamReader("PublicPrivateKey.xml");
string publicprivatekeyxml = reader.ReadToEnd();
RSA.FromXmlString(publicprivatekeyxml);
reader.Close();
byte[] decryptedKey = RSA.Decrypt(getencryptedkey, false);
pwd = System.Text.ASCIIEncoding.Unicode.GetString(decryptedKey);
byte[] dk = null;
byte[] div = null;
crm.getKeysFromPassword(pwd, out dk, out div);
cryptoKey = dk;
cryptoIV = div;
#endregion
string ext = Path.GetExtension(encName).ToLower();
if (ext != ".enc")
{
MessageBox.Show("Please Enter correct File");
return;
}
string dncName = Path.GetDirectoryName(encName) + "\\" + Path.GetFileNameWithoutExtension(encName);
dncName = current.Date.Day.ToString() + current.Date.Month.ToString() + current.Date.Year.ToString() + current.TimeOfDay.Duration().Hours.ToString() + current.TimeOfDay.Duration().Minutes.ToString() + current.TimeOfDay.Duration().Seconds.ToString() + ".wmv";
try
{
if (crm.DecryptData(encName, dncName, cryptoKey, cryptoIV))
{
FileInfo fi = new FileInfo(encName);
FileInfo fi2 = new FileInfo(dncName);
if ((fi.Attributes & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
{ fi.Attributes &= ~FileAttributes.ReadOnly; }
//copy creation and modification time
fi2.CreationTime = fi.CreationTime;
fi2.LastWriteTime = fi.LastWriteTime;
//delete encrypted file
File.Delete(encName);
MessageBox.Show("File Decrypted");
}
else
{
MessageBox.Show("The file can't be decrypted - probably wrong password");
}
}
catch (CryptographicException ex)
{ MessageBox.Show(ex.Message); }
catch (IOException ex)
{ MessageBox.Show(ex.Message); }
catch (UnauthorizedAccessException ex)
{ //i.e. readonly
MessageBox.Show(ex.Message);
}
}
catch (Exception ex)
{ MessageBox.Show(ex.Message); }
}

Answer 1

To copy-protect a video file, the best way to accomplish it used to be apply DRM to it. That way you can restrict how may times it should play or how long it should be available to the user, but that still could be broken via a lot of means.
You cannot make any video 100% copy protected. Please read the article below. If that was the case, the hollywood movies wouldnt be freely available via the torrent networks.
http://www.streamingmedia.com/Articles/Editorial/Featured-Articles/DRM-Is-Dead-79353.aspx