This is an interesting angle I´d not heard before, as cryptography had at least at some point been classified as munitions (maybe still is, I haven't been watching that).
"Okay, in that case, the constitution says you can't infringe my right to it."
Although I would fear going down that path would lead to them saying, "Well, we already infringe on access to certain kinds of munitions, so you can still have encryption, but only the stuff we have a backdoor to." which has been on the agenda before.
Interesting bit of history, PGP was publicly released by Phil Zimmermann. The US government went after him with criminal charges for violating munitions export laws.
He won because he published his source code in a printed book, and was able to effectively argue that his act was protected under the first amendment right to free speech.
The munitions angle for cryptography didn't prevent us from having it, but it did prevent us from EXPORTING it globally. At least if I remember the debate correctly.
This makes me wonder how one would even prove that something were encrypted.
Do encrypted files/data universally follow any sort of pattern? If not, then how would they be discernible from transmitting random bits? Will that be illegal, too?
Note that I'm not talking about any specific existing encryption algorithms or protocols. I am positing that someone could devise a new one that outputs data that is indistinguishable from noise (without breaking the cipher/keys).
The right to bear digital arms.