I wrote:

With respect to possession within the U.S., there aren't any laws stopping you from waving strong cryptography around wherever you like (at least, not yet).

---- ...and in private email, Jim Ray pointed out that showing the shirt to a foreign national might technically violate ITAR... ---- Yeah, I suppose I overstated it a bit. It appears that if the ITAR do cover the shirt (unclear at present, AFAIK -- any news on the CJR, Raph ?), then flashing it at a furriner could constitute a violation. Thanks for the correction. The gist of my previous message remains: No local or state authority in the U.S. (of which I'm aware) classifies strong cryptography as a munition, weapon, etc. I haven't heard of any restrictions on transporting crypto across state lines, either. Unless the Feds start cracking down on high schools, or the Perl-RSA shirt somehow violates some school dress code, (gang colors ? ;) the original questioner need not fret about his son wearing the shirt to school. -Futplex, just another slimy tentacle of the List Maintainer