function show_checksum(checksum)
{
   var _checksum = "";
   for(var i = 0; i < 16; i++){ _checksum = _checksum + checksum.substr(i*8,8)+"&nbsp;"; }
   document.getElementById("checksum").innerHTML = "<p><center>" + _checksum + "</center></p>"
}
function show_checksum_info()
{
   document.getElementById("checksum").innerHTML = "<p><center>&nbsp;</center></p>"
}