function Tdm.addmm(s:string):string;
        var
        i,j:Integer;
        Asc:Byte;
    begin
        Result:='';
        for i:=1 to Length(S) do
             begin
             if (i mod Length(SdString)) = 0 then
                 j:=Length(SdString)
            else
                j:=(i mod Length(SdString));
           Asc:=Byte(S[i]) xor Byte(SdString[j]);
           Result:=Result+IntToHex(Asc,3);
        end;
   end;