This paper relates to a method for fast factoring of large numbers and related topics concerning deciphering messages or documents based on Shor's quantum algorithm. This method is outstandingly useful to reduce the time necessary for large number factorisations (usually involved in information coding for secure transmission) and in particular is the first step for realizing hardware dismember factor to accelerate computation in a classic computer. It has been found and is the object of the present paper a new method that implements the operations performed in the second and third steps of a quantum algorithm (the so-called entanglement and interference operators), providing a substantially increasing in computational speed with respect to the corresponding software realization of a traditional quantum factoring algorithm.