CRC32 o MD5 de un ejecutable

Hola, como puedo saber el CRC32 o MD5 desde un mismo ejecutable con c#

es para proteger una aplicacion, es decir al arracar mi programa que se
autoverifique el CRC32 o MD5


aqui dejo las funciones CRC32 y MD5

public static string GetMD5HashFromFile(string fileName)

{

FileStream file = new FileStream(fileName, FileMode.Open);

MD5 md5 = new MD5CryptoServiceProvider();

byte[] retVal = md5.ComputeHash(file);

file.Close();

StringBuilder sb = new StringBuilder();

for (int i = 0; i < retVal.Length; i++)

{ sb.Append(retVal[i].ToString("x2"));

}

return sb.ToString();

}


public static string GetCrc32( string filePath)

{

int myTimer = Environment.TickCount;


FileStream myStream = new FileStream( filePath , FileMode.Open ,
FileAccess.Read );


long fileSize = myStream.Length;



long[] LookUpTable = new long[ 256 ];

long poly = 0xEDB88320;

long crc32 = 0;


long val;


for( int i = 0 ; i <= 0xFF ; ++i)

{

val = i;

for( int j = 8 ; j > 0 ; --j )

{

if( ( val & 1 ) == 1 )

{

val = ( val >> 1 ) ^ poly ;

}

else

val >>= 1 ;

}

LookUpTable[ i ] = val;

}



byte[] byteArray = new byte[ 4096 ];

int offset = 0 ;

crc32 = 0xFFFFFFFF;


while( offset != fileSize )

{

long dif = fileSize - offset;

if( dif >= 4096 )

{

myStream.Read( byteArray , 0 , 4096 );

offset += 4096;

}

else

{

byteArray = new byte[ dif ];

myStream.Read( byteArray , 0 , byteArray.Length );

offset += byteArray.Length;

}

myStream.Seek( offset , SeekOrigin.Begin );


for( int y = 0 ; y < byteArray.Length ; ++y)

{


crc32 = ( crc32 >> 8 ) ^ LookUpTable[ ( crc32 & 0xFF ) ^ byteArray[ y ] ];

}


}


myStream.Close();


int mySecondTimer = Environment.TickCount;

int ms = mySecondTimer - myTimer;

//MessageBox.Show( "CRC32 "+ ms.ToString() + " Millisec.","Info");

long nret = crc32 ^ 0xFFFFFFFF;


return nret.ToString("X");

}




Gracias
Agustin