CIRCUIT FOR CALCULATING INVERSE ELEMENT ON GF BASED ON STANDARD BASIS

摘要

PURPOSE: A circuit for calculating an inverse element on a GF(Galois Fields) based on standard basis is provided to reduce an arithmetic time on the GF because a basis conversion circuit is not composed. CONSTITUTION: The first register(30) stores data. The second register(40) stores data. A GF multiplier(50) multiplies output signals of the first and second registers(30,40), and outputs the multiplied result. The third selection circuit(85) transmits the output signal of the first register(30) or an output signal of the GF multiplier(50) according to the third selection signal. A four square device(70) receives an output signal of the third selection circuit(85), and multiplies the received signal by the fourth power. The fourth selection circuit(87) transmits the output signal of the second register(40) or the output signal of the GF multiplier(50) according to the fourth selection signal. The first selection circuit(81) transmits a certain element on an inputted GF or an output signal of the four square device(70) to the first register(30) according to the first selection signal. A square device(60) receives the certain element on the inputted GF, squares the received element, and outputs the squared result. The second selection circuit(83) transmits an output signal of the square device(60) or an output signal of the fourth selection circuit(87) to the second register(40) according to the second selection signal(83).