On the one hand, there's already a lot of US legal precedent for encryption as a form of arms, in the form of laws that classify encryption technology as such f

On the one hand, there's already a lot of US legal precedent for encryption as a form of arms, in the form of laws that classify encryption technology as such for export purposes. On the other hand, there's even more US legal precedent demonstrating the Supreme Court thinks that the 2nd Amendment applies very narrowly to a very specific class of arms. The Supreme Court fairly recently decided that my city's former ban on handguns is unconstitutional. This decision has not, however, been construed to also cover local bans on things like throwing knives. Nor, I think, would it cover the bans on things like small rockets, even though they are usable as (and originally invented to be) weapons. I'm inclined to say that the latter body of precedent is the one that the Court would choose to lean on if this were cast as a 2nd Amendment issue.