but curious how it decodes an encryption key. Is motorola encryption now a standardized format for all radios?
It would need to have the encryption key loaded into it to decode any encrypted audio.
There encryption types are standardized, but there is no standard key. Essentially you either have the right key issued to you, or you don't.
And just in case you were going to ask, No, no agency will give you their encryption key. That's sort of like giving some stranger your log in and password to your bank account.
The encryption keys are stored in a keyloader, and in some cases, the guys loading the radios won't know what it is. Encryption keys are highly protected. Someone giving them out to people that are not supposed to have them is a 'career ending decision', and in some cases, will get you an all expense paid stay at the gray bar hotel, sharing a room with a guy named Bubba.