42,620 research outputs found
Efficient multiplication in binary fields
The thesis discusses the basics of efficient multiplication in finite fields,
especially in binary fields. There are two broad approaches: polynomial representation and normal bases, used in software and hardware implementations,
respectively. Due to the advantages of normal bases of low complexity, there is
also a brief introduction to constructing optimal normal bases. Furthermore, as
irreducible polynomials are of fundamental importance for finite fields, the thesis
concludes with some irreducibility test
Construction of Self-Dual Integral Normal Bases in Abelian Extensions of Finite and Local Fields
Let be a finite Galois extension of fields with abelian Galois group
. A self-dual normal basis for is a normal basis with the
additional property that for .
Bayer-Fluckiger and Lenstra have shown that when , then
admits a self-dual normal basis if and only if is odd. If is an
extension of finite fields and , then admits a self-dual normal
basis if and only if the exponent of is not divisible by . In this
paper we construct self-dual normal basis generators for finite extensions of
finite fields whenever they exist.
Now let be a finite extension of \Q_p, let be a finite abelian
Galois extension of odd degree and let \bo_L be the valuation ring of . We
define to be the unique fractional \bo_L-ideal with square equal to
the inverse different of . It is known that a self-dual integral normal
basis exists for if and only if is weakly ramified. Assuming
, we construct such bases whenever they exist
Construction of self-dual normal bases and their complexity
Recent work of Pickett has given a construction of self-dual normal bases for
extensions of finite fields, whenever they exist. In this article we present
these results in an explicit and constructive manner and apply them, through
computer search, to identify the lowest complexity of self-dual normal bases
for extensions of low degree. Comparisons to similar searches amongst normal
bases show that the lowest complexity is often achieved from a self-dual normal
basis
Multiplicative Order of Gauss Periods
We obtain a lower bound on the multiplicative order of Gauss periods which
generate normal bases over finite fields. This bound improves the previous
bound of J. von zur Gathen and I. E. Shparlinski.Comment: 9 page
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