Abstract:
A method of generating cryptographically secure (or unpredictable) pseudo-random numbers uses simple functions whose inverse is not a well-defined function and has a large number of branches, although the inverse could be easily computed on each particular branch. In this way the sequence of numbers is practically unpredictable and at the same time may be generated using very simple functions. A hardware generator of chaos-based pseudo random bit sequences implementing an embodiment of the method comprises:
― circuit means for storing bit strings representing integer numbers of the pseudo-random sequence; ― a shift register coupled to the circuit means; ― a command circuit generating shift commands for the shift register; ― second circuit means for storing the bits output by the shift register; ― an adder modulo 2 summing the bits stored in the second circuit means, generating a bit of the chaos-based pseudo-random bit sequence; ― a second adder summing up the bit strings currently stored in the shift register and in the first circuit means, generating a bit string representing a successive number of the pseudo-random sequence.
Abstract:
Described herein are a molecular memory obtained using DNA strand molecular switches and carbon nanotubes, and a manufacturing method thereof. In particular, the nonvolatile memory is manufactured according to an architecture that envisages the use of carbon nanotubes as electrical connectors and DNA strands as physical means on which to write the information. In other words, the nonvolatile memory is made by means of a set of molecular DNA strand switches, the addressing of which is controlled by molecular wires made up of carbon nanotubes.
Abstract:
In an encryption/decryption system for converting data signals between an unencrypted plaintext format and an encrypted ciphertext format plurality of round modules are provided (10) permitting a respective set of input data signals (TEXT IN) to generate a respective set of output data signals (TEXT OUT) by means of transformation controlled by a round key (SUBKEY). The transformation is identified by at least one map function derived from a chaotic map (14).
Abstract:
A method for generating a random number sequence whose randomness properties are determined a priori , comprises the steps of defining a parametric map; calculating, in function of parameters of the map, the entropy and the Lyapunov exponent of random number sequences obtainable using the parametric map; identifying at least a set of values of parameters for which the entropy and the Lyapunov exponent are positive numbers the map has no attracting point; assigning a pre-established value as a first feedback value and carrying out cyclically the following steps for generating a random number sequence:
(i) determining said parameters inside the set as the numerical values of respective physical quantities; (ii) outputting a random number, according to said map with the parameters and the assigned feedback value; (iii) assigning as new feedback value said output random number.
A circuit, preferably realized using a switched current technique, implements the method of the invention for generating a random bit sequence.
Abstract:
A vehicle comprises at least one semiactive suspension (5) arranged between a vehicle body (2) and a wheel (4) and having a damping coefficient that can be varied in a controlled way by an actuator (14) governed by a control device (18). The control device comprises an accelerometric sensor (15) generating a vehicle body acceleration signal; a potentiometer (16) generating a suspension position signal; a signal conditioning unit (21) for the calculation of the vehicle body speed and the damping speed; a fuzzy control unit (23) which calculates the subsequent position of the actuator on the basis of the vehicle body speed and of the damping speed; and a driving unit (21) which generates a control signal (S1) for the actuator.