Patent ID: 8280938

Claim:
An apparatus having multiplier, adders and registers for computing semi-sequential Galois Field (GF) GF(2 n ) multiplication with two GF(2 n ) operands, n being a positive even integer,comprising: two single ground field GF(2 m ) multipliers, for respectively inputting a high-order element and a low-order element of the composite field of one of said two operands in parallel and inputting a high-order element and a low-order element of the composite field of the other operand of said two operands sequentially, and generating a plurality of GF(2 m ) partial products, n=2m; at least a constant multiplier, connected to said the single ground field GF(2 m ) multiplier inputting the high-order elements of said two operands; and a plurality of single GF(2 m ) adders; wherein one of said two operands is mapped from GF(2 n )into GF(2 m ) through an operation of mapping into composite field to send the high-order element and the low-order element of the composite field of the one operand to the two single ground field GF(2 m ) multipliers, the high-order element and a low-order element of the composite field of the other operand pass through a respective single matrix conversion and then are send to the two single ground field GF(2 m ) multipliers, said plurality of GF(2 m )partial products pass through said constant multiplier and said plurality of single GF(2 m ) adders to obtain a high-order element and a low-order element of a GF((2 m ) 2 ) product, and said high-order element and said low-order element of said GF((2 m ) 2 ) product are mapped back to GF(2 n ) field to accomplish said GF(2 n ) multiplication.