Actually, only RSA public-key cryptography is based on that asymmetry, and even that is not precisely correct. And RSA is considered the most probable candidate to be broken at some time of the bunch of algorithms that are used. Even ssh uses DSA (at least you should, and not use RSA if you are paranoid) which is based on the assumed difficulty of calculating discrete logarithms in finite fields. If you are even more paranoid, use something that is based on elliptic curves.
Actually, changing clothes at security to provided, standardized suits and have your clothes packed together and transported in the luggage compartment should be fairly safe as well. Of course, everyone would look the same in flight then...
Look e.g. here: http://www.business-sites.philips.com/3dsolutions/home/index.page
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