In an embodiment the present invention relates to a method comprising: inputting data in binary form; arranging the input data in segments; determining a plurality of values based on respective ones of said segments; using said values to determine locations where a predetermined transformation is to be applied to a sequence of bits; performing said predetermined transformation on said sequence of bits at each of said locations; outputting the sequence of bits as first output data. The present invention can be applied to encryption and decryption of data, data comparison and verification, and random data generation.