i'm trying to read a binary file (for example an executable) into a string, then write it back

FileStream fs = new FileStream("C:\\tvin.exe", FileMode.Open);
BinaryReader br = new BinaryReader(fs);
byte[] bin = br.ReadBytes(Convert.ToInt32(fs.Length));
System.Text.Encoding enc = System.Text.Encoding.ASCII;
string myString = enc.GetString(bin);
fs.Close();
br.Close();
System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
byte[] rebin = encoding.GetBytes(myString);
FileStream fs2 = new FileStream("C:\\tvout.exe", FileMode.Create);
BinaryWriter bw = new BinaryWriter(fs2);
bw.Write(rebin);
fs2.Close();
bw.Close();

this does not work (the result has exactly the same size in bytes but can't run)

if i do bw.Write(bin) the result is ok, but i must save it to a string