The usual technique is to claim the encoding technique, the decoding technique, and the data structures expressed by and expressing the technique. There's also

The usual technique is to claim the encoding technique, the decoding technique, and the data structures expressed by and expressing the technique. There's also equivalents and the doctrine of induced infringement. The patent courts and ITC have looked very unfavorably on First Amendment claims and on defenses based on lack of infringement within the USA and technologies with alternative non-infringing uses not being liable. The Supreme Court is less extremist than patent courts on insisting that patents pre-empt the Constitution, but the Supreme Court takes very few cases and you'd already have spent millions to get there and -- most importantly -- the patent courts largely don't consider Supreme Court cases to be necessarily binding precedent next time around.