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Blum Blum Shub takes the form + =, where M = pq is the product of two large primes p and q.At each step of the algorithm, some output is derived from x n+1; the output is commonly either the bit parity of x n+1 or one or more of the least significant bits of x n+1.
Then, f(r) = 0, which can be rearranged to express r k as a linear combination of powers of r less than k. This equation can be used to reduce away any powers of r with exponent e ≥ k. For example, if f(x) = x 2 + 1 and r is the imaginary unit i, then i 2 + 1 = 0, or i 2 = −1. This allows us to define the complex product:
We can think of a pseudorandom number generator (PRNG) as a function that transforms a series of bits known as the state into a new state and a random number. That is, given a PRNG function and an initial state s t a t e 0 {\displaystyle \mathrm {state} _{0}} , we can repeatedly use the PRNG to generate a sequence of states and random numbers.
The MIXMAX generator is a family of pseudorandom number generators (PRNG) and is based on Anosov C-systems (Anosov diffeomorphism) and Kolmogorov K-systems (Kolmogorov automorphism). It was introduced in a 1986 preprint by G. Savvidy and N. Ter-Arutyunyan-Savvidy and published in 1991.
The Mersenne Twister is a general-purpose pseudorandom number generator (PRNG) developed in 1997 by Makoto Matsumoto (松本 眞) and Takuji Nishimura (西村 拓士). [1] [2] Its name derives from the choice of a Mersenne prime as its period length. The Mersenne Twister was designed specifically to rectify most of the flaws found in older PRNGs.
A prime sieve or prime number sieve is a fast type of algorithm for finding primes. There are many prime sieves. The simple sieve of Eratosthenes (250s BCE), the sieve of Sundaram (1934), the still faster but more complicated sieve of Atkin [1] (2003), sieve of Pritchard (1979), and various wheel sieves [2] are most common.
For example, a modulus of F 5 = 2 32 + 1 might seem attractive, as the outputs can be easily mapped to a 32-bit word 0 ≤ X i − 1 < 2 32. However, a seed of X 0 = 6700417 (which divides 2 32 + 1) or any multiple would lead to an output with a period of only 640.
The value x is in the range 0 to 25, but if x + n or x − n are not in this range then 26 should be added or subtracted.) The replacement remains the same throughout the message, so the cipher is classed as a type of monoalphabetic substitution , as opposed to polyalphabetic substitution .