Abstract: A method for secure conversion between two different random markings used for cryptographic functions, converts a first binary data word, masked by a binary mask word according to a first masking process, into a corresponding second binary data word, masked by said binary mask word according to a second masking process, the first and second binary data words and the binary mask word including corresponding pluralities of bits, wherein each of the pluralities of the bits includes a least significant bit, a first bit, and at least one i-th bit i?2.

Abstract: A method for transforming data with a secret parameter in an elliptic curve cryptosystem based on an elliptic curve defined over an underlying binary polynomial field, includes multiplying a point of the elliptic curve, and representing the data to be transformed by a scalar representing the secret parameter, wherein the multiplying includes performing at least one point addition operation and at least one point doubling operation on points of the elliptic curve. The point addition operation includes a first sequence of elementary field operations, and the point doubling operation includes a second sequence of elementary field operations, both the first and the second sequences of elementary field operations including a field inversion of coordinates of the elliptic curve points. A representation of the elliptic curve points in affine coordinates is provided and the first and second sequences of elementary field operations are balanced.

Abstract: A random binary sequence generator for generating a random binary sequence adapted to be used for producing random numbers, includes at least one logic circuit corresponding to an associated finite-state machine having a state-transition function including states arranged to form cycles of states, wherein the at least one logic circuit has a set of logic circuit inputs and a set of logic circuit outputs fed back to the logic circuit inputs; the associated finite-state machine is autonomous and asynchronous; the state-transition function is void of loops; and any of the cycles of states has either a minimum length equal to three states, in case the cycle is stable, or a minimum length of two states, in case the cycle is meta-stable.

Abstract: An apparatus for generating random data includes a raw random sequence source adapted to generate a raw random sequence and a digital post processor adapted to process the raw random sequence to generate the random data, wherein the digital post-processor includes a synchronous finite state machine having at least one input adapted to repeatedly receive a current value of the raw random sequence and at least one output to provide a current output value depending on previous values of the raw random sequence.

Abstract: A combinatorial key-dependent network suitable for the encryption/decryption of data on buses and in memories of data-processing devices, has a number of layers, where each layer has a number of elementary building blocks operating on very small block sizes. A generic building block acts on a small number of input data bits, which are divided into two groups of m and n bits, respectively. The m input bits, which are passed to the output intact, are used to select k out of 2mk key bits by a multiplexer circuit; the k bits are then used to select an (n×n)-bit reversible transformation acting on the remaining n input bits to produce the corresponding n output bits. The total number of the key bits in the building block is thus 2mk, which can easily he made larger that m+n. An inverse building block is the same except that the reversible transformations are replaced by their inverses.