As a follow up to the previous post, this article from Wired is interesting. It suggests the best way to disable an RFID chip.
All passports issued by the US State Department after January 1 will have always-on radio frequency identification chips, making it easy for officials – and hackers – to grab your personal stats. Getting paranoid about strangers slurping up your identity? Here’s what you can do about it. But be careful – tampering with a passport is punishable by 25 years in prison.
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The best approach? Hammer time. Hitting the chip with a blunt, hard object should disable it. A nonworking RFID doesn’t invalidate the passport, so you can still use it.