1. An apparatus for generating a digital value based on a semiconductor process variation, the apparatus comprising: a generating unit to generate a plurality of digital values, based on the semiconductor process variation; and a processing unit to process the digital values and to provide a first digital value, wherein the generating unit comprises a plurality of physically unclonable functions (PUFs), at least a portion of the PUFs is manufactured by differently applying at least one parameter causing the semiconductor process variation, and the PUFs generate the digital values.