280,074 research outputs found
New construction of single-cycle T-function families
The single cycle T-function is a particular permutation function with complex algebraic structures, maximum period and efficient implementation in software and hardware. In this paper, on the basis of existing methods, we present a new construction using a class of single cycle T-functions meeting certain conditions to construct a family of new single cycle T-functions, and we also give the numeration lower bound for the newly constructed single cycle T- functions
New construction of single cycle T-function families
The single cycle T-function is a particular permutation function with complex algebraic structures, maximum period and efficient implementation in software and hardware. In this paper, on the basis of existing methods, by using a class of single cycle T-functions that satisfy some certain conditions, we first present a new construction of single cycle T-function families. Unlike the previous approaches, this method can construct multiple single cycle T-functions at once. Then the mathematical proof of the feasibility is given. Next the numeration for the newly constructed single cycle T-functions is also investigated. Finally, this paper is end up with a discussion of the properties which these newly constructed functions preserve, such as linear complexity and stability (k-error complexity), as well as a comparison with previous construction methods
Regular and almost universal hashing: an efficient implementation
Random hashing can provide guarantees regarding the performance of data
structures such as hash tables---even in an adversarial setting. Many existing
families of hash functions are universal: given two data objects, the
probability that they have the same hash value is low given that we pick hash
functions at random. However, universality fails to ensure that all hash
functions are well behaved. We further require regularity: when picking data
objects at random they should have a low probability of having the same hash
value, for any fixed hash function. We present the efficient implementation of
a family of non-cryptographic hash functions (PM+) offering good running times,
good memory usage as well as distinguishing theoretical guarantees: almost
universality and component-wise regularity. On a variety of platforms, our
implementations are comparable to the state of the art in performance. On
recent Intel processors, PM+ achieves a speed of 4.7 bytes per cycle for 32-bit
outputs and 3.3 bytes per cycle for 64-bit outputs. We review vectorization
through SIMD instructions (e.g., AVX2) and optimizations for superscalar
execution.Comment: accepted for publication in Software: Practice and Experience in
September 201
Construction of 2-factors in the middle layer of the discrete cube
Define the middle layer graph as the graph whose vertex set consists of all
bitstrings of length that have exactly or entries equal to 1,
with an edge between any two vertices for which the corresponding bitstrings
differ in exactly one bit. In this work we present an inductive construction of
a large family of 2-factors in the middle layer graph for all . We
also investigate how the choice of certain parameters used in the construction
affects the number and lengths of the cycles in the resulting 2-factor
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