METHOD FOR IMPROVING UNPREDICTABILITY OF OUTPUT OF PSEUDO-RANDOM NUMBER GENERATORS

A method for performing computations in a mathematical system which exhibits a positive Lyapunov exponent, or exhibits chaotic behavior, comprises varying a parameter of the system. When employed in cryptography, such as, e.g., in a pseudo-random number generator of a stream-cipher algorithm, in a block-cipher system or a HASH/MAC system, unpredictability may be improved. In a similar system, a computational method comprises multiplying two numbers and manipulating at least one of the most significant bits of the number resulting from the multiplication to produce an output. A number derived from a division of two numbers may be used for deriving an output. In a system for generating a sequence of numbers, an array of counters is updated at each computational step, whereby a carry value is added to each counter. Fixed-point arithmetic may be employed. A method of determining an identification value and for concurrently encrypting and /or decrypting a set of data is disclosed.