This is exactly the type of bullshit I'm talking about when I try to stress privacy to people I know and they think I'm a lunatic. Most people don't want to hear what "could" happen, only what has happened in the past.
Hand over information to someone you trust (in that case the Govt. of your country who proclaim that they welcome Jews); someone who wants to use it against not you gains control of it via takeover (in that case a bunch of psychotics who will murder you because in 1933 your grandma ticked "Jewish" on the census form).
It isn't far fetched nonsense, it is tried and tested.
Http://ibmandtheholocaust.com/