Examples include comparison of a part key to machine keys. Examples include identification of a part key assigned to a given machine identifier in a part key mapping of a part received by a computing device, the part key mapping including a plurality of part keys assigned to a plurality of machine identifiers. Examples also include comparison of the identified part key to machine keys stored on the computing device to determine whether the identified part key matches any of the machine keys, and based at least in part on a result of the determination, enabling or inhibiting further utilization of the part.