| 摘要 |
PROBLEM TO BE SOLVED: To obtain an inexpensive data operation unit with a small circuit scale. SOLUTION: This data operation unit uses data belonging to a finite field whose characteristic is 2 and whose bit size is 2 m (m is a natural number being 2 or over) for an arithmetic object. This data operation unit is realized by a combination of arithmetic circuits whose arithmetic object is data belonging to a finite field whose characteristic is 2 and whose bit size is m. Preferably, the above bit size 2 m is equal to a power of 2, and arithmetic circuit whose arithmetic object is data belonging to a finite field whose bit size is m is realized by a combination of arithmetic circuits whose arithmetic object is data belonging to a finite field whose bit size is m/2, that is a half the bit size m. Simirlarly, the arithmetic circuit aiming at data whose bit size is m/2 is realize by a combination of arithmetic circuits aiming at data whose bit size is m/4, that is, a half of m/2. In this way, an arithmetic circuit is sequentially realized by a combination of arithmetic circuits aiming at data whose bit size is half that of the arithmetic circuit,.
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