Galois-Field Arithmetic Module Generator (AMG) supports two types of
hardware algorithms for parallel multipliers. In the following, we
briefly describe the hardware algorithms that can be handled by GF-AMG.
Multipliers
Mastrovito multiplier
Mastrovito multiplier is a class of parallel multipliers over Galois fields based on
polynomial basis representations.
The polynomial basis of GF(pm) is given as a vector
(βm-1,βm-2, …, β0)
. As an example, consider a Galois field GF(28) obtained by
an irreducible polynomial
IP(x)=x8+x4+x3+x+1. When IP(β)=0,
a vector (β7, β6, …,
β0) is a polynomial basis. Figure 1 shows the
architecture of Mastrovito multipliers handled in GF-ACG, which consists
of Matrix generator and Matrix operator. The Matrix generator first
generates a matrix determined by a reminder which is given by the
division of multiplicand by polynomial basis. The Matrix operator then
performs the multiplication of the multiplier (i.e., another input) and
the generated matrix and finally produces the product. Such Mastrovito
multipiler is known as a GF parallel multiplier with the minimal area cost.
> generate mastrovito multipliers
Figure 1. Architecture of a Mastrovito multiplier
Massey-Omura parallel multiplier
Massey-Omura parallel multiplier is a class of parallel multipliers over
Galois fields based on normal basis representations. The normal basis of
GF(pm) is given as a vector
(αpm-1,
αpm-2,
…,αp0), where
α is the normal element of GF(pm). As an example,
consider a Galois field GF(28) obtained by an irreducible
polynomial IP(x)=x8+x4+x3+x+1. When
IP(β)=0 and α=β5, a vector
(α27,α26, …,α20) is a normal basis. Figure 2 show the
architecutre of Massey-Omura parallel multipliers handled in GF-ACG,
which consist of Partial Product Generator (PPG) and Accumulator (ACC).
The PPG stage first generates partial products from the multiplicand and
multiplier in parallel. The ACC stage then performs multi-operand
addition for all the generated partial products and produces the final
product. Such GF multipliers based on normal basis representations are
useful for constructing circuits including squaring operators such as
exponentiation and inverse circuits.
> generate massey-omura
parallel multipliers
Figure 2. Architecture of a Massey-Omura parallel multiplier
References
-
A. Halbutogullari and C.K. Koc,
"Mastrovito multiplier for general irreducible polynomials",
IEEE Trans. Computers, Vol. 49, No. 5, pp. 503--518, May 2000.
-
A. Reyhani-Masoleh and M.A. Hasan,
"A New Construction of Massey-Omura Parallel Multiplier over GF(2m)",
IEEE Trans. Computers, vol. 51, no. 5, pp. 511--520, May 2001.
-
R.C. Mullin, I.M. Onyszchuk, S.A, Vanstone, and R.M. Wilson,
"Optimal Normal Basis in GF(pn)",
Discrete Applied Math, vol.~22, pp.~149--161, 1988/1989.
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