They can't stop people from doing math, but they can stop people from sharing high-entropy (i.e. "looks encrypted") data. There are of course workarounds (e.g.

They can't stop people from doing math, but they can stop people from sharing high-entropy (i.e. "looks encrypted") data. There are of course workarounds (e.g. steganography), but if you add enough friction then the average person won't bother, and those who do try to maintain their privacy will be at even greater risk of detection and punishment.