A fixed logic integrated circuit is disclosed. The integrated circuit comprises a unique code generator configured to generate a code having a value which is intrinsically unique to the integrated circuit, an enrolment pattern generator configured to generate an enrolment pattern based on the unique code. The integrated circuit is configured to transmit the enrolment pattern to an external enrolment device and to receive enabling data from the external enrolment device. Optionally, the integrated circuit may include memory for storing remotely-generated enabling data. The integrated circuit comprises a configuration file generator configured to generate configuration data using the remotely-generated enabling data and the unique code, and a feature activation module configured to activate and/or disable features of the integrated circuit and/or customise the integrated circuit in dependence upon the configuration data.