Facial recognition scrambler: the device, worn anywhere on the head or neck, would detect facial-recognition attempts from any device (hello, google glass) and return invalid data to the offending device. Cyber counter attack measures: You hit me, I hit you. an eye for an eye. Hack me and I'll hack back. It would be an autonomous system whose job would be to strike back at any attempt at hacking, spying and the likes. it would be based on gradual responses. the harder they try to get in your computer, the harder the counter attack will be. Imagine, that script kiddie that has been bothering you, his computer rendered inoperable... encryption spoofer: for the most paranoid, data will look normal and no one would suspect it's something else, but underneath the mask is a set of encryption keys that check on each other constantly autonomously. If the keys are valid, you get to see the actual data. if any bit is different, you can't access any of the real data. additionally, the data itself has a self-destruct mechanism so that any attempt to brute-force it will corrupt the data and make it unreadable and unrecoverable after a very limited set of allowed tries.
The cyber counter attack you talked about are common and really was preceded by the USSR's nuclear program. Fail Deadly is the true term. Think something even exists akin to your encryption spoofer, I know some encryption software renders data completely fucked after 2-3 fails
There are some people who have designed face-paint that confuses facial recognition algorithms. Not an electronic device, but it has the same effect. It also makes you look like a drunken clown.
Just point some bright IR LEDs at your face, it will show up as a bright spot on cameras: http://www.youtube.com/watch?v=jOH9XhsP3iI With TrueCrypt you can create a hidden volume within another volume. If you don't know the password, the hidden volume can't be distinguished from the empty space: http://www.truecrypt.org/hiddenvolume
