not quite correct...
the "free speech" test for encryption regards protecting the computer language that performs the mathematics required being protected speech.
See Phil Zimmermann's essay regarding PGP.
Free speech for political discourse is essentially supported by encryption. Hence, the above article is a good checkpoint to observe, when discussing how governments try and complain about encryption.
The arguments which emphasized mathematics as a form of free speech (and by extension computer instructions) are much purer in intent and delivery regarding the governments ability to interfere with technology, and have the benefit of being widely discussed in the context of "munitions".
And of course there's the obligatory.