I need to research before I make statements. You sound like you have researched and know that some other hardware other than the keyboard needs to be present in the iMac for Touch ID to work? If so, what is that hardware? Is it not possible that the hardware is in the keyboard and only a software upgrade is needed within the iMac in order for the keyboard Touch ID to work?Buying the keyboard will not install the authentication hardware in your 2017 iMac.