A method includes in part, generating an electro-optical frequency map (EOFM) of an active layer of an integrated circuit (IC), retrieving a reference map of the IC, comparing the EOFM of the IC with the reference map to determine whether there is a match between an intensity of an identified region in the EOFM map and an intensity of a corresponding region of the reference map, and detecting one or more hardware trojans in the IC if there is no match. The reference map may be associated with a layout of an IC known not to include hardware trojans. The reference map also may be a second EOFM associated with the IC. Alternatively, the reference map may be generated by applying power to the IC, and applying a clock signal to the IC.