An integrated circuit identification device (ICID) to be incorporated into an integrated circuit (IC) includes an array of electronic cells in which the magnitude of an output signal of each cell is a function of randomly occurring parametric variations which vary from cell-to-cell. The ICID also includes a circuit for measuring the output of each cell and for producing output data having a value reflecting the particular combination of measured characteristics of all of the elements of the array. When we make the number of elements in the array large enough, we insure that to a high degree of probability, the pattern of measured array cell characteristics for an ICID embedded in any one IC will be unique and distinguishable from such patterns measured by ICIDs embedded in millions of other ICs. Thus the value of the output data produced by an ICID circuit acts as a unique "fingerprint" for the IC in which it is installed, and can be used as a unique identification (ID) for that IC.