Provided is an apparatus for generating digital values to provide a random digital value. The apparatus may generate the digital value based on a semiconductor process variation. The apparatus may include 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. The generating unit may include a plurality of physically unclonable functions (PUFs). A parameter may be differently applied to the PUFs, and the PUFs may generate the digital values.