Single key ÆS has been more of the norm than the exception for years from the manufacturers, especially with procurement of the radios using Federal grant dollars that require encryption. It's then a zero effort for an agency to keyload the radios while dropping in the codeplug and using it full time for its operations. My former team and I assisted numerous departments in my County to secure their internal comms and at the same time never lost interoperability after we rolled out P25 in 2017.