An important distinction is that what's not allowed is "messages encoded for the purpose of obscuring their meaning", not encryption altogether, which means thi

An important distinction is that what's not allowed is "messages encoded for the purpose of obscuring their meaning", not encryption altogether, which means things like digital signatures can be permissible, if the public key is available through well-known means or included as a separate part of the transmission. https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4) https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4)