"messages encoded for the purpose of obscuring their meaning" https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4) https://www.ecfr.gov/current/title-4

"messages encoded for the purpose of obscuring their meaning" 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) It's intentionally broad, and gives exceptions for controlling satellites as the only real exception. People try to fight that publishing encryption keys would mean that you are within the intent of the law, I struggled decades ago trying to create a digital voice mode while every OM told me I was trying to encrypt things. sigh.