A circuitry access system for controlling access to addressable circuit elements of an integrated circuit. The circuitry access system includes a first storage element having a first listing of unique identifiers each identifier representing one of the addressable circuit elements. A selector distinguishes a first subset of unique identifiers from the first listing. A second storage element receives and stores the first subset in an arrangement that does not include an indication of the absence of any unique identifier of the first listing that is not included in the first subset. An output of second storage element allows a user of the integrated circuit to access one or more of the addressable circuit elements corresponding to the first subset of unique identifiers. A method of controlling access to addressable circuit elements is also provided.