Note that you're not allowed to use encryption or engage in commercial activities on the amateur bands. (In the USA but probably in other countries as well.)
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)