Disclosed is a physical unclonable function generator circuit and method. In one embodiment, physical unclonable function (PUF) generator includes: a PUF cell array that comprises a plurality of bit cells, wherein each of the plurality of bit cells comprises at least two access transistors, at least one enable transistor, and at least two storage nodes, wherein the at least two storage nodes are pre-configured with substantially the same voltages allowing each of the plurality of bit cells having a first metastable logical state; a PUF control circuit coupled to the PUF cell array, wherein the PUF control circuit is configured to access the plurality of bit cells to determine second logical states by turning on the at least one enable transistor and turning off the at least two access transistors of each of the plurality of bit cells, and based on the second logical states of the plurality of bit cells, to generate a PUF output; and a noise injector coupled to the PUF control circuit and the PUF cell array, wherein the noise injector is configured to create stressed operation conditions to evaluate stability of the plurality of bit cells.