A system for identifying of presence of protected data in an unknown file includes a processor coupled to a memory storing instructions, the processor being configured to implement the instructions to apply a sliding window process to generate one or more fragments of length, for each generated fragment, check whether information about the generated fragment exists in a library of known fragments of protected data, and if the information about the generated fragment from the unknown file exists in the library of known fragments of protected data, perform steps to reflect an existence of the information about the generated fragment.