A method of measuring signal change including the steps of: performing at least one iteration step based on one or more non-linear dynamical functions on a first input signal, or sample of a first input signal, to produce a first iteration value; performing at least a second iteration step by repeating the at least one iteration step based on one or more non-linear dynamical functions on the first iteration value to produce a second iteration value; storing iteration values generated from the first input signal or sample of said first input signal; performing at least one iteration step based on one or more non-linear dynamical functions on at least a second input signal, or sample of a second input signal, to produce a first iteration value from the second input signal; performing at least a second iteration step for the second input signal by repeating the at least one iteration step based on one or more chaos functions on the first iteration value from the second input signal to produce a second iteration value; storing iteration result values generated from the second input signal, or sample of said second input signal; subtracting one set of iteration values generated from either the first or second input signal or samples of said first or second input signals from the corresponding iteration values generated from the other input signal or sample; and determining the difference between the first or second input signal or samples of said first or second input signals by determining the number of iterations before the difference between the iteration result values increases, wherein the number of iterations before the difference between the iteration result values increases is proportional to the relative difference between the first input signal and the second input signal and/or samples thereof. performing at least one iteration step based on one or more non-linear dynamical functions on a first input signal, or sample of a first input signal, to produce a first iteration value; performing at least a second iteration step by repeating the at least one iteration step based on one or more non-linear dynamical functions on the first iteration value to produce a second iteration value; storing iteration values generated from the first input signal or sample of said first input signal; performing at least one iteration step based on one or more non-linear dynamical functions on at least a second input signal, or sample of a second input signal, to produce a first iteration value from the second input signal; performing at least a second iteration step for the second input signal by repeating the at least one iteration step based on one or more chaos functions on the first iteration value from the second input signal to produce a second iteration value; storing iteration result values generated from the second input signal, or sample of said second input signal; subtracting one set of iteration values generated from either the first or second input signal or samples of said first or second input signals from the corresponding iteration values generated from the other input signal or sample; and determining the difference between the first or second input signal or samples of said first or second input signals by determining the number of iterations before the difference between the iteration result values increases,