function TFormRSACipher.GetMultiplInvers(ModBase, Ks: Integer): Integer;
var
   q, d0, d1, d2, y0, y1, y2: Integer;
begin
   d0 := ModBase;
   d1 := Ks;
   y0 := 0;
   y1 := 1;
   while (d1 > 1) do
   begin
      q := d0 div d1;
      d2 := d0 mod d1;
      y2 := y0 - q * y1;
      d0 := d1;
      d1 := d2;
      y0 := y1;
      y1 := y2;
   end;
   if y1 < 0 then
      y1 := y1 + ModBase;
   Result := y1;
end;