Title
Predicting nonlinear pseudorandom number generators
Abstract
Let p be a prime and let a and b be elements of the finite field F-p of p elements. The inversive congruential generator (ICG) is a sequence (u(n)) of pseudorandom numbers defined by the relation u(n+1) = au(n)(-1n) +b modp. We show that if sufficiently many of the most significant bits of several consecutive values un of the ICG are given, one can recover the initial value u(0) ( even in the case where the coefficients a and b are not known). We also obtain similar results for the quadratic congruential generator (QCG), v(n+1) = f(v(n)) mod p, where f is an element of F-p[X]. This suggests that for cryptographic applications ICG and QCG should be used with great care. Our results are somewhat similar to those known for the linear congruential generator (LCG), x(n+1) = ax(n) + b mod p, but they apply only to much longer bit strings. We also estimate limits of some heuristic approaches, which still remain much weaker than those known for LCG.
Year
DOI
Venue
2005
10.1090/S0025-5718-04-01698-9
MATHEMATICS OF COMPUTATION
Keywords
Field
DocType
finite field,pseudorandom number generator
Prime (order theory),Finite field,Mod,Combinatorics,Linear congruential generator,Quadratic equation,Random number generation,Mathematics,Pseudorandom number generator,Inversive congruential generator
Journal
Volume
Issue
ISSN
74
251
0025-5718
Citations 
PageRank 
References 
23
1.16
20
Authors
4
Name
Order
Citations
PageRank
Simon R. Blackburn135736.95
Domingo Gomez-perez26110.22
Jaime Gutierrez315418.15
Igor E. Shparlinski41339164.66