I just don't see anything fundamentally unique about an encrypted communications stream that would require it to be used on the ham bands for 'furthering the radio arts.' Any stream being developed or tested for use over the air should be able to be effectively tested in the clear as allowed by amateur rules. Then further testing (incorporating encryption) can be done over internet or closed circuits. It seems to me that encryption as such is unlikely to have any fundamental effect on the outcome of on-air testing.