My first NFC-capable Android device (running Lollipop) is on its way. I've been doing some research, and got some info on how NFC events are handled internally, but I'd like some more practical information on how careful I need to be when I have NFC enabled. For example:

  • I've read that the NFC is only on while the screen is on. Is this universally true?
  • If I just want to set up some custom tags to control settings on my device (around the house, work, car), is there a way to whitelist the tags I want to trust, and reject or require manual confirmation of any other tags? (I'm guessing if this functionality exists it would require a third party app?)
  • Is it possible for a malicious device somewhere masquerading as, for example, a simple URL tag to use Android Beam or similar functionality to skim information off my device without my knowledge?
  • Pretty sure #1 is false. Commented Sep 24, 2015 at 2:20

1 Answer 1


It sounds like you're overthinking the capabilities of NFC. Most devices are configured so that the phone must be unlocked in order for an NFC to be triggered (this can be overridden with an app). Unless you place you phone on a tag with the screen on and unlocked, the tag won't be read.

  • Right, but what if I do deliberately tap something expecting it to just be, say, a URL, and instead it tries to skim information from my device. Is such a thing possible?
    – glibdud
    Commented Aug 26, 2015 at 18:01
  • It definitely is possible for a tag to not do what you think and there is no way of finding out until scanned. But this is a similar concern to the risks you take using public Wi-Fi or having NFC-chipped credit cards that can be scanned right through your wallet. Personally, I haven't seen an abundance (or any, for that matter) of public NFC tags asking to be scanned. I use NFC tags specifically for what you are looking to do- like setting a timer when I put clothes in the dryer. If I saw a tag out in public, I would think long and hard before scanning it.
    – paulmz
    Commented Aug 26, 2015 at 18:27

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